Play Index Relaunched--Free Trial /
Blog Post
B-R on Twitter / Facebook
S-R.com: Baseball | Basketball | Football | Hockey | Olympics
B-R on Twitter / Facebook
S-R.com: Baseball | Basketball | Football | Hockey | Olympics
You Are Here > Baseball-Reference.com > Leaders & Records > Single-Season Leaders & Records for Losses
Create Custom Leaderboards
The Baseball-Reference.com Play Index's Batting Season Finder lets you create your own custom leaderboards by team, age, position, years, or any other common criteria. View Sample Leaderboards created with the batting season finder.
Single-Season Leaders & Records for Losses
+ - Indicates Hall of Famer. Bold indicates active player.
Only players who finished in the top 40 for the majors in a season will appear on this list. Leaders from the current season are only included for rate stats after July 1st.
| Rank | Player (age that year) | Losses | Year | Throws |
|---|---|---|---|---|
| 1. | John Coleman (20) | 48 | 1883 | R |
| 2. | Will White (25) | 42 | 1880 | R |
| 3. | Larry McKeon (18) | 41 | 1884 | |
| 4. | George Bradley (26) | 40 | 1879 | R |
| Jim McCormick (22) | 40 | 1879 | R | |
| 6. | Kid Carsey (20) | 37 | 1891 | R |
| George Cobb (26) | 37 | 1892 | ||
| Henry Porter (30) | 37 | 1888 | R | |
| 9. | Bill Hutchison (32) | 36 | 1892 | R |
| Stump Wiedman (25) | 36 | 1886 | R | |
| 11. | Jim Devlin (27) | 35 | 1876 | R |
| Red Donahue (24) | 35 | 1897 | R | |
| Pud Galvin+ (23) | 35 | 1880 | R | |
| Hardie Henderson (22) | 35 | 1885 | R | |
| Fleury Sullivan (22) | 35 | 1884 | ||
| Adonis Terry (19) | 35 | 1884 | R | |
| 17. | Mark Baldwin (25) | 34 | 1889 | R |
| Bob Barr (27) | 34 | 1884 | R | |
| Matt Kilroy (20) | 34 | 1886 | L | |
| Bobby Mathews (24) | 34 | 1876 | R | |
| Al Mays (22) | 34 | 1887 | ||
| Amos Rusie+ (19) | 34 | 1890 | R | |
| 23. | Jersey Bakely (24) | 33 | 1888 | R |
| Hardie Henderson (20) | 33 | 1883 | R | |
| Harry McCormick (23) | 33 | 1879 | R | |
| Frank Mountain (23) | 33 | 1883 | R | |
| Lee Richmond (25) | 33 | 1882 | L | |
| Dupee Shaw (25) | 33 | 1884 | L | |
| Jim Whitney (23) | 33 | 1881 | R | |
| 30. | John Harkins (25) | 32 | 1884 | R |
| Lee Richmond (23) | 32 | 1880 | L | |
| Jim Whitney (27) | 32 | 1885 | R | |
| Jim Whitney (28) | 32 | 1886 | R | |
| 34. | Billy Crowell (21) | 31 | 1887 | R |
| Charley Radbourn+ (31) | 31 | 1886 | R | |
| Amos Rusie+ (21) | 31 | 1892 | R | |
| Dupee Shaw (27) | 31 | 1886 | L | |
| Sam Weaver (22) | 31 | 1878 | R | |
| Will White (24) | 31 | 1879 | R | |
| 40. | Jersey Bakely (20) | 30 | 1884 | R |
| Ed Beatin (23) | 30 | 1890 | L | |
| Ted Breitenstein (26) | 30 | 1895 | L | |
| John Ewing (26) | 30 | 1889 | R | |
| Jim Hughey (30) | 30 | 1899 | R | |
| Jack Lynch (29) | 30 | 1886 | R | |
| Jim McCormick (24) | 30 | 1881 | R | |
| Jim McCormick (25) | 30 | 1882 | R | |
| Toad Ramsey (23) | 30 | 1888 | L | |
| Phenomenal Smith (22) | 30 | 1887 | L | |
| Mickey Welch+ (20) | 30 | 1880 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| 51. | Tommy Bond (24) | 29 | 1880 | R |
| Bert Cunningham (22) | 29 | 1888 | R | |
| Red Ehret (20) | 29 | 1889 | R | |
| Pud Galvin+ (26) | 29 | 1883 | R | |
| Bill Hart (30) | 29 | 1896 | R | |
| John Healy (20) | 29 | 1887 | R | |
| Silver King (23) | 29 | 1891 | R | |
| Hank O'Day (25) | 29 | 1888 | R | |
| Jack Taylor (25) | 29 | 1898 | R | |
| Vic Willis+ (29) | 29 | 1905 | R | |
| 61. | Mark Baldwin (27) | 28 | 1891 | R |
| Hugh Daily (36) | 28 | 1884 | R | |
| Duke Esper (24) | 28 | 1893 | L | |
| Bill Hill (21) | 28 | 1896 | L | |
| Doc Landis (27) | 28 | 1882 | ||
| Al Mays (21) | 28 | 1886 | ||
| Jim McCormick (23) | 28 | 1880 | R | |
| Hank O'Day (21) | 28 | 1884 | R | |
| Gus Weyhing (20) | 28 | 1887 | R | |
| 70. | Mark Baldwin (28) | 27 | 1892 | R |
| George Bell (35) | 27 | 1910 | R | |
| Charlie Buffinton (24) | 27 | 1885 | R | |
| Bill Carrick (25) | 27 | 1899 | R | |
| Paul Derringer (26) | 27 | 1933 | R | |
| Chick Fraser (22) | 27 | 1896 | R | |
| Pud Galvin+ (22) | 27 | 1879 | R | |
| Bill Hart (31) | 27 | 1897 | R | |
| Pink Hawley (21) | 27 | 1894 | R | |
| Tim Keefe+ (24) | 27 | 1881 | R | |
| Tim Keefe+ (26) | 27 | 1883 | R | |
| Phil Knell (26) | 27 | 1891 | L | |
| Tony Mullane (27) | 27 | 1886 | R | |
| Toad Ramsey (21) | 27 | 1886 | L | |
| Toad Ramsey (22) | 27 | 1887 | L | |
| Willie Sudhoff (23) | 27 | 1898 | R | |
| Park Swartzel (23) | 27 | 1889 | R | |
| Dummy Taylor (26) | 27 | 1901 | R | |
| 88. | Al Atkinson (23) | 26 | 1884 | R |
| Ted Breitenstein (27) | 26 | 1896 | L | |
| Dory Dean (23) | 26 | 1876 | R | |
| George Derby (23) | 26 | 1881 | R | |
| Gus Dorner (29) | 26 | 1906 | R | |
| Pete Dowling () | 26 | 1901 | L | |
| Pud Galvin+ (28) | 26 | 1885 | R | |
| Bob Groom (24) | 26 | 1909 | R | |
| George Haddock (23) | 26 | 1890 | R | |
| Tim Keefe+ (25) | 26 | 1882 | R | |
| Frank Killen (21) | 26 | 1892 | L | |
| John Kirby (21) | 26 | 1886 | R | |
| Terry Larkin () | 26 | 1878 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Tony Mullane (25) | 26 | 1884 | R | |
| Tony Mullane (32) | 26 | 1891 | R | |
| Jack Neagle (26) | 26 | 1884 | R | |
| Lee Richmond (24) | 26 | 1881 | L | |
| Dupee Shaw (26) | 26 | 1885 | L | |
| Harry Staley (22) | 26 | 1889 | R | |
| Happy Townsend (25) | 26 | 1904 | R | |
| Gus Weyhing (31) | 26 | 1898 | R | |
| 109. | Jersey Bakely (26) | 25 | 1890 | R |
| Ben Cantwell (33) | 25 | 1935 | R | |
| Jim Devlin (28) | 25 | 1877 | R | |
| Charlie Ferguson (21) | 25 | 1884 | R | |
| Patsy Flaherty (27) | 25 | 1903 | L | |
| Pud Galvin+ (31) | 25 | 1888 | R | |
| Charlie Getzien (21) | 25 | 1885 | R | |
| Charlie Getzien (24) | 25 | 1888 | R | |
| Fred Glade (29) | 25 | 1905 | R | |
| Bill Hutchison (30) | 25 | 1890 | R | |
| Walter Johnson+ (21) | 25 | 1909 | R | |
| Oscar Jones (24) | 25 | 1904 | R | |
| Matt Kilroy (23) | 25 | 1889 | L | |
| Terry Larkin () | 25 | 1877 | R | |
| Jim McCormick (27) | 25 | 1884 | R | |
| Stoney McGlynn (35) | 25 | 1907 | R | |
| Harry McIntire (26) | 25 | 1905 | R | |
| Sadie McMahon (24) | 25 | 1892 | R | |
| Jock Menefee (26) | 25 | 1894 | R | |
| Mike Morrison (20) | 25 | 1887 | R | |
| Scott Perry (29) | 25 | 1920 | R | |
| Charley Radbourn+ (28) | 25 | 1883 | R | |
| Bugs Raymond (26) | 25 | 1908 | R | |
| Red Ruffing+ (23) | 25 | 1928 | R | |
| Ed Seward (20) | 25 | 1887 | R | |
| Harry Staley (23) | 25 | 1890 | R | |
| Vic Willis+ (28) | 25 | 1904 | R | |
| Irv Young (28) | 25 | 1906 | L | |
| 137. | Mark Baldwin (26) | 24 | 1890 | R |
| Bob Barr (33) | 24 | 1890 | R | |
| Henry Boyle (24) | 24 | 1885 | R | |
| Henry Boyle (26) | 24 | 1887 | R | |
| Ted Breitenstein (24) | 24 | 1893 | L | |
| Joe Bush (23) | 24 | 1916 | R | |
| Pat Caraway (25) | 24 | 1931 | L | |
| Dad Clarke (31) | 24 | 1896 | R | |
| Roger Craig (32) | 24 | 1962 | R | |
| Ed Crane (30) | 24 | 1892 | R | |
| Bert Cunningham (24) | 24 | 1890 | R | |
| Cliff Curtis (28) | 24 | 1910 | R | |
| Red Donahue (23) | 24 | 1896 | R | |
| Jack Fisher (26) | 24 | 1965 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Chick Fraser (30) | 24 | 1904 | R | |
| Pud Galvin+ (24) | 24 | 1881 | R | |
| Kid Gleason (25) | 24 | 1892 | R | |
| Dolly Gray (33) | 24 | 1931 | R | |
| John Healy (21) | 24 | 1888 | R | |
| Jim Hughey (29) | 24 | 1898 | R | |
| Tom Hughes (25) | 24 | 1904 | R | |
| Bill Hutchison (33) | 24 | 1893 | R | |
| John Keefe (23) | 24 | 1890 | L | |
| Silver King (24) | 24 | 1892 | R | |
| Sadie McMahon (23) | 24 | 1891 | R | |
| Ed Morris (22) | 24 | 1885 | L | |
| Tony Mullane (23) | 24 | 1882 | R | |
| Henry Porter (29) | 24 | 1887 | R | |
| Billy Rhines (22) | 24 | 1891 | R | |
| Lev Shreve (19) | 24 | 1888 | R | |
| John Ward+ (20) | 24 | 1880 | R | |
| Stump Wiedman (22) | 24 | 1883 | R | |
| Stump Wiedman (24) | 24 | 1885 | R | |
| 170. | Red Ames (31) | 23 | 1914 | R |
| Henry Boyle (28) | 23 | 1889 | R | |
| George Bradley (24) | 23 | 1877 | R | |
| Ted Breitenstein (25) | 23 | 1894 | L | |
| Buster Brown (28) | 23 | 1910 | R | |
| Elton Chamberlain (23) | 23 | 1891 | R | |
| Elton Chamberlain (24) | 23 | 1892 | R | |
| Larry Corcoran (24) | 23 | 1884 | R | |
| Jack Cronin (30) | 23 | 1904 | R | |
| Ed Daily (22) | 23 | 1885 | R | |
| Frank Dwyer (23) | 23 | 1891 | R | |
| George Ferguson (25) | 23 | 1909 | R | |
| Pud Galvin+ (25) | 23 | 1882 | R | |
| Henry Gruber (26) | 23 | 1890 | R | |
| John Healy (19) | 23 | 1886 | R | |
| Guy Hecker (27) | 23 | 1883 | R | |
| Guy Hecker (29) | 23 | 1885 | R | |
| Guy Hecker (30) | 23 | 1886 | R | |
| Hardie Henderson (21) | 23 | 1884 | R | |
| Tom Hughes (22) | 23 | 1901 | R | |
| Beany Jacobson (23) | 23 | 1904 | L | |
| Frank Killen (26) | 23 | 1897 | L | |
| Terry Larkin () | 23 | 1879 | R | |
| Sam Leever (27) | 23 | 1899 | R | |
| Vive Lindaman (28) | 23 | 1906 | R | |
| Dolf Luque (31) | 23 | 1922 | R | |
| Jim McCormick (30) | 23 | 1887 | R | |
| Charlie McCullough (24) | 23 | 1890 | ||
| Doc McJames (22) | 23 | 1897 | R | |
| Lee Meadows (21) | 23 | 1916 | R | |
| Frank Meinke (20) | 23 | 1884 | ||
| Rank | Player (age that year) | Losses | Year | Throws |
| Win Mercer (20) | 23 | 1894 | R | |
| Win Mercer (21) | 23 | 1895 | R | |
| Ed Morris (25) | 23 | 1888 | L | |
| George Mullin (23) | 23 | 1904 | R | |
| Elmer Myers (22) | 23 | 1916 | R | |
| Rollie Naylor (28) | 23 | 1920 | R | |
| Jack Neagle (25) | 23 | 1883 | R | |
| Tricky Nichols (26) | 23 | 1877 | R | |
| Orval Overall (24) | 23 | 1905 | R | |
| Case Patten (30) | 23 | 1904 | L | |
| Charley Radbourn+ (32) | 23 | 1887 | R | |
| Eddie Rommel (23) | 23 | 1921 | R | |
| Amos Rusie+ (24) | 23 | 1895 | R | |
| Scott Stratton (23) | 23 | 1893 | R | |
| Mickey Welch+ (23) | 23 | 1883 | R | |
| Kaiser Wilhelm (31) | 23 | 1905 | R | |
| Irv Young (29) | 23 | 1907 | L | |
| 218. | Jersey Bakely (25) | 22 | 1889 | R |
| Bill Bonham (25) | 22 | 1974 | R | |
| Henry Boyle (27) | 22 | 1888 | R | |
| Bill Carrick (26) | 22 | 1900 | R | |
| Bill Carrick (27) | 22 | 1901 | R | |
| Dan Casey (27) | 22 | 1890 | L | |
| Roger Craig (33) | 22 | 1963 | R | |
| Ed Crane (29) | 22 | 1891 | R | |
| Art Ditmar (27) | 22 | 1956 | R | |
| Frank Dwyer (26) | 22 | 1894 | R | |
| Dick Ellsworth (26) | 22 | 1966 | L | |
| Pud Galvin+ (27) | 22 | 1884 | R | |
| Charlie Getzien (25) | 22 | 1889 | R | |
| Kid Gleason (24) | 22 | 1891 | R | |
| Kid Gleason (26) | 22 | 1893 | R | |
| Dan Griner (25) | 22 | 1913 | R | |
| Henry Gruber (27) | 22 | 1891 | R | |
| Pink Hawley (22) | 22 | 1895 | R | |
| Harry Howell (28) | 22 | 1905 | R | |
| Si Johnson (27) | 22 | 1934 | R | |
| Randy Jones (24) | 22 | 1974 | L | |
| Brickyard Kennedy (30) | 22 | 1898 | R | |
| Silver King (22) | 22 | 1890 | R | |
| Charlie Knepper (28) | 22 | 1899 | R | |
| Lon Knight (23) | 22 | 1876 | R | |
| Joe Lake (27) | 22 | 1908 | R | |
| Rube Marquard+ (27) | 22 | 1914 | L | |
| Denny McLain (27) | 22 | 1971 | R | |
| Ed Morris (24) | 22 | 1887 | L | |
| Frank Mountain (22) | 22 | 1882 | R | |
| Hugh Mulcahy (26) | 22 | 1940 | R | |
| Tony Mullane (34) | 22 | 1893 | R | |
| The Only Nolan (20) | 22 | 1878 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Al Orth (30) | 22 | 1903 | R | |
| Case Patten (29) | 22 | 1903 | L | |
| Case Patten (31) | 22 | 1905 | L | |
| Big Jeff Pfeffer (24) | 22 | 1906 | R | |
| Togie Pittinger (31) | 22 | 1903 | R | |
| Jack Quinn (31) | 22 | 1915 | R | |
| Eppa Rixey+ (29) | 22 | 1920 | L | |
| Robin Roberts+ (30) | 22 | 1957 | R | |
| Steve Rogers (24) | 22 | 1974 | R | |
| Red Ruffing+ (24) | 22 | 1929 | R | |
| Jack Stivetts (23) | 22 | 1891 | R | |
| Lefty Tyler (22) | 22 | 1912 | L | |
| Tom Vickery (23) | 22 | 1890 | R | |
| Sam Weaver (27) | 22 | 1883 | R | |
| Mickey Welch+ (26) | 22 | 1886 | R | |
| Will White (28) | 22 | 1883 | R | |
| Kaiser Wilhelm (34) | 22 | 1908 | R | |
| Weldon Wyckoff (23) | 22 | 1915 | R | |
| Joe Yeager (22) | 22 | 1898 | R | |
| Cy Young+ (24) | 22 | 1891 | R | |
| 271. | Steve Arlin (26) | 21 | 1972 | R |
| Stan Bahnsen (28) | 21 | 1973 | R | |
| Jesse Barnes (24) | 21 | 1917 | R | |
| Fred Beebe (29) | 21 | 1909 | R | |
| Ed Brandt (23) | 21 | 1928 | L | |
| John Clarkson+ (25) | 21 | 1887 | R | |
| Ed Cushman (33) | 21 | 1885 | L | |
| Ed Cushman (38) | 21 | 1890 | L | |
| Hooks Dauss (30) | 21 | 1920 | R | |
| Paul Derringer (27) | 21 | 1934 | R | |
| Murry Dickson (35) | 21 | 1952 | R | |
| Bill Dinneen (26) | 21 | 1902 | R | |
| Denny Driscoll (27) | 21 | 1883 | L | |
| Jack Dunn (25) | 21 | 1898 | R | |
| Mal Eason (26) | 21 | 1905 | R | |
| Red Ehret (25) | 21 | 1894 | R | |
| Dana Fillingim (26) | 21 | 1920 | R | |
| Russ Ford (29) | 21 | 1912 | R | |
| Frank Foreman (26) | 21 | 1889 | L | |
| Chick Fraser (31) | 21 | 1905 | R | |
| Pud Galvin+ (29) | 21 | 1886 | R | |
| Pud Galvin+ (30) | 21 | 1887 | R | |
| Bump Hadley (27) | 21 | 1932 | R | |
| Bob Harmon (25) | 21 | 1913 | R | |
| Harry Harper (24) | 21 | 1919 | L | |
| Joe Harris (24) | 21 | 1906 | R | |
| Lum Harris (28) | 21 | 1943 | R | |
| Slim Harriss (30) | 21 | 1927 | R | |
| Pink Hawley (23) | 21 | 1896 | R | |
| John Healy (23) | 21 | 1890 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Harry Howell (24) | 21 | 1901 | R | |
| Harry Howell (27) | 21 | 1904 | R | |
| Bill Hutchison (35) | 21 | 1895 | R | |
| Larry Jackson (34) | 21 | 1965 | R | |
| Sam Jones (32) | 21 | 1925 | R | |
| Harry Kelley (31) | 21 | 1937 | R | |
| Matt Kilroy (22) | 21 | 1888 | L | |
| Silver King (20) | 21 | 1888 | R | |
| Phil Knell (29) | 21 | 1894 | L | |
| Don Larsen (24) | 21 | 1954 | R | |
| Mickey Lolich (33) | 21 | 1974 | L | |
| Jack Lynch (28) | 21 | 1885 | R | |
| Ted Lyons+ (32) | 21 | 1933 | R | |
| Mike Maroth (25) | 21 | 2003 | L | |
| Al Mattern (26) | 21 | 1909 | R | |
| Al Maul (27) | 21 | 1893 | R | |
| Harry McIntire (27) | 21 | 1906 | R | |
| Sadie McMahon (22) | 21 | 1890 | R | |
| George Mullin (24) | 21 | 1905 | R | |
| Joe Oeschger (30) | 21 | 1922 | R | |
| Al Orth (34) | 21 | 1907 | R | |
| George Pechiney (24) | 21 | 1886 | R | |
| Barney Pelty (26) | 21 | 1907 | R | |
| Togie Pittinger (32) | 21 | 1904 | R | |
| Henry Porter (27) | 21 | 1885 | R | |
| Charley Radbourn+ (30) | 21 | 1885 | R | |
| Eppa Rixey+ (26) | 21 | 1917 | L | |
| Nap Rucker (27) | 21 | 1912 | L | |
| Amos Rusie+ (22) | 21 | 1893 | R | |
| Fred Sanford (28) | 21 | 1948 | R | |
| Jack Scott (28) | 21 | 1920 | R | |
| Jack Scott (35) | 21 | 1927 | R | |
| Billy Serad (22) | 21 | 1885 | R | |
| Jack Stivetts (22) | 21 | 1890 | R | |
| Bill Sweeney () | 21 | 1884 | R | |
| Charlie Sweeney (22) | 21 | 1885 | R | |
| Jack Taylor (23) | 21 | 1896 | R | |
| Jack Taylor (25) | 21 | 1899 | R | |
| Jack Taylor (31) | 21 | 1905 | R | |
| Jim Tobin (29) | 21 | 1942 | R | |
| Bucky Walters (27) | 21 | 1936 | R | |
| Mickey Welch+ (24) | 21 | 1884 | R | |
| Gus Weyhing (22) | 21 | 1889 | R | |
| Gus Weyhing (25) | 21 | 1892 | R | |
| Gus Weyhing (28) | 21 | 1895 | R | |
| Gus Weyhing (32) | 21 | 1899 | R | |
| Will White (23) | 21 | 1878 | R | |
| Jim Whitney (24) | 21 | 1882 | R | |
| Jim Whitney (25) | 21 | 1883 | R | |
| Jim Whitney (29) | 21 | 1887 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Jim Whitney (30) | 21 | 1888 | R | |
| Stump Wiedman (23) | 21 | 1884 | R | |
| Stan Yerkes (27) | 21 | 1902 | R | |
| Cy Young+ (27) | 21 | 1894 | R | |
| Cy Young+ (39) | 21 | 1906 | R | |
| Irv Young (27) | 21 | 1905 | L | |
| 357. | Nate Andrews (29) | 20 | 1943 | R |
| Bill Bailey (27) | 20 | 1915 | L | |
| Mark Baldwin (29) | 20 | 1893 | R | |
| Jesse Barnes (31) | 20 | 1924 | R | |
| Dick Barrett (38) | 20 | 1945 | R | |
| Boom-Boom Beck (28) | 20 | 1933 | R | |
| Rube Benton (22) | 20 | 1912 | L | |
| Joe Bowman (26) | 20 | 1936 | R | |
| Harry Byrd (28) | 20 | 1953 | R | |
| Howie Camnitz (31) | 20 | 1913 | R | |
| Steve Carlton+ (28) | 20 | 1973 | L | |
| George Caster (30) | 20 | 1938 | R | |
| Jack Chesbro+ (34) | 20 | 1908 | R | |
| John Clarkson+ (26) | 20 | 1888 | R | |
| Pete Conway (19) | 20 | 1886 | R | |
| Larry Corcoran (23) | 20 | 1883 | R | |
| Nick Cullop (26) | 20 | 1914 | L | |
| Ed Cushman (34) | 20 | 1886 | L | |
| George Derby (24) | 20 | 1882 | R | |
| Murry Dickson (37) | 20 | 1954 | R | |
| Bill Dinneen (23) | 20 | 1899 | R | |
| Bill Doak (26) | 20 | 1917 | R | |
| Phil Douglas (27) | 20 | 1917 | R | |
| Pete Dowling () | 20 | 1898 | L | |
| Howard Ehmke (31) | 20 | 1925 | R | |
| Red Ehret (23) | 20 | 1892 | R | |
| Dick Ellsworth (22) | 20 | 1962 | L | |
| Cy Falkenberg (25) | 20 | 1906 | R | |
| Turk Farrell (28) | 20 | 1962 | R | |
| Charlie Ferguson (22) | 20 | 1885 | R | |
| Cherokee Fisher (31) | 20 | 1876 | R | |
| Frank Foreman (28) | 20 | 1891 | L | |
| Chick Fraser (24) | 20 | 1898 | R | |
| Chick Fraser (32) | 20 | 1906 | R | |
| Ned Garvin (27) | 20 | 1901 | R | |
| Milt Gaston (34) | 20 | 1930 | R | |
| Les German (27) | 20 | 1896 | R | |
| Frank Gilmore (23) | 20 | 1887 | ||
| Bob Groom (29) | 20 | 1914 | R | |
| Bump Hadley (28) | 20 | 1933 | R | |
| Noodles Hahn (21) | 20 | 1900 | L | |
| Jesse Haines+ (26) | 20 | 1920 | R | |
| John Harkins (26) | 20 | 1885 | R | |
| Slim Harriss (25) | 20 | 1922 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Guy Hecker (28) | 20 | 1884 | R | |
| Glen Hobbie (24) | 20 | 1960 | R | |
| Art Houtteman (24) | 20 | 1952 | R | |
| Tom Hughes (26) | 20 | 1905 | R | |
| Bert Inks (24) | 20 | 1895 | L | |
| Al Jackson (26) | 20 | 1962 | L | |
| Al Jackson (29) | 20 | 1965 | L | |
| Walter Johnson+ (28) | 20 | 1916 | R | |
| Sam Jones (26) | 20 | 1919 | R | |
| Sam Jones (29) | 20 | 1955 | R | |
| Tim Keefe+ (29) | 20 | 1886 | R | |
| Alex Kellner (25) | 20 | 1950 | L | |
| Brickyard Kennedy (25) | 20 | 1893 | R | |
| Brickyard Kennedy (26) | 20 | 1894 | R | |
| Brickyard Kennedy (28) | 20 | 1896 | R | |
| Brickyard Kennedy (29) | 20 | 1897 | R | |
| Vern Kennedy (32) | 20 | 1939 | R | |
| Henry Keupper (27) | 20 | 1914 | L | |
| Frank Killen (27) | 20 | 1898 | L | |
| Ed Killian (27) | 20 | 1904 | L | |
| Sam Kimber (31) | 20 | 1884 | R | |
| Brian Kingman (25) | 20 | 1980 | R | |
| Clay Kirby (21) | 20 | 1969 | R | |
| Jerry Koosman (34) | 20 | 1977 | L | |
| Ted Lyons+ (28) | 20 | 1929 | R | |
| Joe McGinnity+ (30) | 20 | 1901 | R | |
| Joe McGinnity+ (32) | 20 | 1903 | R | |
| Harry McIntire (29) | 20 | 1908 | R | |
| Doc McJames (21) | 20 | 1896 | R | |
| Lee Meadows (24) | 20 | 1919 | R | |
| Jouett Meekin (25) | 20 | 1892 | R | |
| Rube Melton (25) | 20 | 1942 | R | |
| Win Mercer (23) | 20 | 1897 | R | |
| Roscoe Miller (25) | 20 | 1902 | R | |
| Ed Morris (23) | 20 | 1886 | L | |
| Hugh Mulcahy (24) | 20 | 1938 | R | |
| George Mullin (26) | 20 | 1907 | R | |
| Jack Nabors (28) | 20 | 1916 | R | |
| Bobo Newsom (26) | 20 | 1934 | R | |
| Bobo Newsom (33) | 20 | 1941 | R | |
| Bobo Newsom (37) | 20 | 1945 | R | |
| Phil Niekro+ (38) | 20 | 1977 | R | |
| Phil Niekro+ (40) | 20 | 1979 | R | |
| Hank O'Day (24) | 20 | 1887 | R | |
| Jim Pastorius (26) | 20 | 1908 | L | |
| Orlando Pena (29) | 20 | 1963 | R | |
| Charley Radbourn+ (27) | 20 | 1882 | R | |
| Ken Raffensberger (26) | 20 | 1944 | L | |
| Pedro Ramos (26) | 20 | 1961 | R | |
| Bill Reidy (27) | 20 | 1901 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Gordon Rhodes (28) | 20 | 1936 | R | |
| Bob Rush (24) | 20 | 1950 | R | |
| Amos Rusie+ (20) | 20 | 1891 | R | |
| Jack Russell (24) | 20 | 1930 | R | |
| Ed Scott (29) | 20 | 1900 | R | |
| Jim Scott (25) | 20 | 1913 | R | |
| Billy Serad (21) | 20 | 1884 | R | |
| Charlie Smith (27) | 20 | 1907 | R | |
| Eddie Smith (28) | 20 | 1942 | L | |
| George Smith (29) | 20 | 1921 | R | |
| Phenomenal Smith (23) | 20 | 1888 | L | |
| Tracy Stallard (26) | 20 | 1964 | R | |
| Chuck Stobbs (27) | 20 | 1957 | L | |
| Mel Stottlemyre (24) | 20 | 1966 | R | |
| Willie Sudhoff (30) | 20 | 1905 | R | |
| Jack Taylor (24) | 20 | 1897 | R | |
| Luis Tiant (28) | 20 | 1969 | R | |
| Lee Viau (22) | 20 | 1889 | R | |
| Alex Voss (26) | 20 | 1884 | R | |
| Ed Walsh+ (29) | 20 | 1910 | R | |
| Carl Weilman (23) | 20 | 1913 | L | |
| Gus Weyhing (24) | 20 | 1891 | R | |
| Doc White (23) | 20 | 1902 | L | |
| Wild Bill Widner (22) | 20 | 1889 | R | |
| Stump Wiedman (21) | 20 | 1882 | R | |
| Bill Wight (26) | 20 | 1948 | L | |
| Kaiser Wilhelm (30) | 20 | 1904 | R | |
| Roy Wilkinson (28) | 20 | 1921 | R | |
| Vic Willis+ (26) | 20 | 1902 | R | |
| Wilbur Wood (31) | 20 | 1973 | L | |
| Wilbur Wood (33) | 20 | 1975 | L | |
| Clyde Wright (33) | 20 | 1974 | L | |
| George Zettlein (31) | 20 | 1876 | R | |
| 484. | Steve Arlin (25) | 19 | 1971 | R |
| Kirtley Baker (21) | 19 | 1890 | R | |
| George Baumgardner (21) | 19 | 1913 | R | |
| Fred Beebe (27) | 19 | 1907 | R | |
| Joe Benz (28) | 19 | 1914 | R | |
| Jim Bibby (29) | 19 | 1974 | R | |
| George Blaeholder (29) | 19 | 1933 | R | |
| Vida Blue (27) | 19 | 1977 | L | |
| Jeremy Bonderman (20) | 19 | 2003 | R | |
| Tommy Bond (22) | 19 | 1878 | R | |
| Tommy Bond (23) | 19 | 1879 | R | |
| George Bradley (23) | 19 | 1876 | R | |
| Ed Brandt (30) | 19 | 1935 | L | |
| Ted Breitenstein (23) | 19 | 1892 | L | |
| Lou Brissie (26) | 19 | 1950 | L | |
| George Brunet (32) | 19 | 1967 | L | |
| Howie Camnitz (32) | 19 | 1914 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Steve Carlton+ (25) | 19 | 1970 | L | |
| Ownie Carroll (29) | 19 | 1932 | R | |
| George Caster (29) | 19 | 1937 | R | |
| George Caster (32) | 19 | 1940 | R | |
| Ken Chase (25) | 19 | 1939 | L | |
| Eddie Cicotte (34) | 19 | 1918 | R | |
| Galen Cisco (28) | 19 | 1964 | R | |
| John Clarkson+ (27) | 19 | 1889 | R | |
| John Clarkson+ (29) | 19 | 1891 | R | |
| Watty Clark (27) | 19 | 1929 | L | |
| Jim Conway (30) | 19 | 1889 | R | |
| Wilbur Cooper (31) | 19 | 1923 | L | |
| Ed Crane (28) | 19 | 1890 | R | |
| Bert Cunningham (23) | 19 | 1889 | R | |
| Omar Daal (28) | 19 | 2000 | L | |
| Hugh Daily (35) | 19 | 1883 | R | |
| Jose DeLeon (24) | 19 | 1985 | R | |
| Jose DeLeon (29) | 19 | 1990 | R | |
| Paul Derringer (29) | 19 | 1936 | R | |
| Murry Dickson (36) | 19 | 1953 | R | |
| Walt Dickson (33) | 19 | 1912 | R | |
| Walt Dickson (35) | 19 | 1914 | R | |
| Bill Dinneen (30) | 19 | 1906 | R | |
| Ed Doheny (24) | 19 | 1898 | L | |
| Gus Dorner (31) | 19 | 1908 | R | |
| Bill Duggleby (32) | 19 | 1906 | R | |
| Jesse Duryea (29) | 19 | 1889 | R | |
| Red Ehret (26) | 19 | 1895 | R | |
| Sammy Ellis (25) | 19 | 1966 | R | |
| Scott Erickson (25) | 19 | 1993 | R | |
| Roy Evans (28) | 19 | 1902 | R | |
| Bob Ewing (34) | 19 | 1907 | R | |
| Wes Ferrell (29) | 19 | 1937 | R | |
| Howie Fox (28) | 19 | 1949 | R | |
| Chick Fraser (23) | 19 | 1897 | R | |
| Larry French (30) | 19 | 1938 | L | |
| Bob Friend (28) | 19 | 1959 | R | |
| Bob Friend (30) | 19 | 1961 | R | |
| Sam Frock (27) | 19 | 1910 | R | |
| Wayne Garland (26) | 19 | 1977 | R | |
| Milt Gaston (33) | 19 | 1929 | R | |
| Milt Gaston (38) | 19 | 1934 | R | |
| Hank Gastright (26) | 19 | 1891 | R | |
| Joe Genewich (27) | 19 | 1924 | R | |
| Al Gerheauser (26) | 19 | 1943 | L | |
| Fred Goldsmith (27) | 19 | 1883 | R | |
| Dolly Gray (30) | 19 | 1909 | L | |
| Dolly Gray (31) | 19 | 1910 | L | |
| Bill Greif (24) | 19 | 1974 | R | |
| Burleigh Grimes+ (31) | 19 | 1925 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Bob Groom (32) | 19 | 1917 | R | |
| Ad Gumbert (23) | 19 | 1892 | R | |
| Warren Hacker (28) | 19 | 1953 | R | |
| George Haddock (22) | 19 | 1889 | R | |
| Noodles Hahn (22) | 19 | 1901 | L | |
| Jesse Haines+ (30) | 19 | 1924 | R | |
| George Hemming (25) | 19 | 1894 | R | |
| Hardie Henderson (23) | 19 | 1886 | R | |
| Kirby Higbe (25) | 19 | 1940 | R | |
| Chief Hogsett (33) | 19 | 1937 | L | |
| Jay Hook (25) | 19 | 1962 | R | |
| Bill Hutchison (31) | 19 | 1891 | R | |
| Elmer Jacobs (24) | 19 | 1917 | R | |
| Al Javery (26) | 19 | 1944 | R | |
| Si Johnson (24) | 19 | 1931 | R | |
| Si Johnson (35) | 19 | 1942 | R | |
| Bobby Jones (31) | 19 | 2001 | R | |
| Cowboy Jones (25) | 19 | 1900 | L | |
| George Kahler (22) | 19 | 1912 | R | |
| Ed Karger (23) | 19 | 1906 | L | |
| Ed Karger (24) | 19 | 1907 | L | |
| Tim Keefe+ (30) | 19 | 1887 | R | |
| Ted Kennedy (21) | 19 | 1886 | ||
| Matt Kilroy (21) | 19 | 1887 | L | |
| Dave Koslo (26) | 19 | 1946 | L | |
| Gene Krapp (28) | 19 | 1915 | R | |
| Lerrin LaGrow (25) | 19 | 1974 | R | |
| Wayne LaMaster (30) | 19 | 1937 | L | |
| Rick Langford (25) | 19 | 1977 | R | |
| Tim Leary (31) | 19 | 1990 | R | |
| Dutch Leonard (31) | 19 | 1940 | R | |
| Mickey Lolich (29) | 19 | 1970 | L | |
| Albie Lopez (29) | 19 | 2001 | R | |
| Tom Lovett (27) | 19 | 1891 | ||
| Dolf Luque (30) | 19 | 1921 | R | |
| Art Mahaffey (23) | 19 | 1961 | R | |
| Al Mattern (27) | 19 | 1910 | R | |
| Darrell May (32) | 19 | 2004 | L | |
| Erskine Mayer (24) | 19 | 1914 | R | |
| Kirk McCaskill (30) | 19 | 1991 | R | |
| Mike McDermott (32) | 19 | 1895 | R | |
| Chappie McFarland (28) | 19 | 1903 | R | |
| Willie McGill (20) | 19 | 1894 | L | |
| Frank Miller (31) | 19 | 1917 | R | |
| Al Milnar (27) | 19 | 1941 | L | |
| Sam Moffett (27) | 19 | 1884 | R | |
| Earl Moore (31) | 19 | 1911 | R | |
| Mike Moore (27) | 19 | 1987 | R | |
| Van Mungo (25) | 19 | 1936 | R | |
| Bobo Newsom (34) | 19 | 1942 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Kid Nichols+ (20) | 19 | 1890 | R | |
| Kid Nichols+ (29) | 19 | 1899 | R | |
| Darby O'Brien (21) | 19 | 1888 | R | |
| Al Orth (24) | 19 | 1897 | R | |
| Tom Parrott (26) | 19 | 1894 | R | |
| Gaylord Perry+ (34) | 19 | 1973 | R | |
| Scott Perry (27) | 19 | 1918 | R | |
| Herman Pillette (26) | 19 | 1923 | R | |
| Henry Porter (28) | 19 | 1886 | R | |
| Jack Powell (24) | 19 | 1899 | R | |
| Jack Powell (26) | 19 | 1901 | R | |
| Jack Powell (28) | 19 | 1903 | R | |
| Jack Powell (29) | 19 | 1904 | R | |
| Jack Powell (36) | 19 | 1911 | R | |
| Ken Raffensberger (32) | 19 | 1950 | L | |
| Pedro Ramos (24) | 19 | 1959 | R | |
| Jimmy Ring (26) | 19 | 1921 | R | |
| Eddie Rommel (25) | 19 | 1923 | R | |
| Nap Rucker (23) | 19 | 1908 | L | |
| Nap Rucker (24) | 19 | 1909 | L | |
| Dick Rudolph (27) | 19 | 1915 | R | |
| Don Rudolph (31) | 19 | 1963 | L | |
| Ben Sanders (27) | 19 | 1892 | R | |
| Pete Schneider (19) | 19 | 1915 | R | |
| Pete Schneider (20) | 19 | 1916 | R | |
| Pete Schneider (21) | 19 | 1917 | R | |
| Al Schulz (27) | 19 | 1916 | L | |
| Ed Seward (21) | 19 | 1888 | R | |
| Cy Seymour (25) | 19 | 1898 | L | |
| Allen Sothoron (24) | 19 | 1917 | R | |
| Warren Spahn+ (31) | 19 | 1952 | L | |
| Tully Sparks (27) | 19 | 1902 | R | |
| Paul Splittorff (27) | 19 | 1974 | L | |
| Bill Steele (25) | 19 | 1911 | R | |
| Lefty Stewart (31) | 19 | 1932 | L | |
| Bill Stoneman (25) | 19 | 1969 | R | |
| Scott Stratton (22) | 19 | 1892 | R | |
| Jack Sutthoff (31) | 19 | 1904 | R | |
| Frank Tanana (20) | 19 | 1974 | L | |
| Jack Taylor (27) | 19 | 1901 | R | |
| Jack Taylor (30) | 19 | 1904 | R | |
| Jim Tobin (31) | 19 | 1944 | R | |
| Jim Tobin (32) | 19 | 1945 | R | |
| Virgil Trucks (35) | 19 | 1952 | R | |
| Rube Vickers (30) | 19 | 1908 | R | |
| Rube Waddell+ (27) | 19 | 1904 | L | |
| John Ward+ (19) | 19 | 1879 | R | |
| Jack Warhop (27) | 19 | 1912 | R | |
| Carl Weilman (25) | 19 | 1915 | L | |
| Mickey Welch+ (28) | 19 | 1888 | R | |
| Rank | Player (age that year) | Losses | Year | Throws |
| Snake Wiltse (30) | 19 | 1902 | L | |
| Ted Wingfield (25) | 19 | 1925 | R | |
| George Winter (30) | 19 | 1908 | R | |
| Rick Wise (32) | 19 | 1978 | R | |
| Wilbur Wood (32) | 19 | 1974 | L | |
| Clyde Wright (32) | 19 | 1973 | L | |
| Early Wynn+ (28) | 19 | 1948 | R | |
| Cy Young+ (30) | 19 | 1897 | R | |
| Cy Young+ (33) | 19 | 1900 | R | |
| Cy Young+ (38) | 19 | 1905 | R | |
| Matt Young (26) | 19 | 1985 | L |
Note that seasons prior to 1876 are not included in single-season marks, but are included in career marks.
