You Are Here > Baseball-Reference.com > Blog >

SITE NEWS: We are moving all of our site and company news into a single blog for Sports-Reference.com. We'll tag all B-R content, so you can quickly and easily find the content you want.

Also, our existing B-R blog rss feed will be redirected to the new site's feed.

Baseball-Reference.com ยป Sports Reference

For more from Andy and the gang, check out their new site High Heat Stats.

Average number of players used per team

Posted by Andy on June 24, 2010

Click through to see all-time data on the average number of pitchers and hitters to appear for each team. Teams use a lot more players today than they used to.

Here are the average number of hitters and pitchers used each year per team. These numbers are calculated from the Pitching Encyclopedia and Batting Encyclopedia, taking the total number of hitters or batters appearing in a season and dividing by the number of teams n the league that year.

The black line is the ratio of hitters to pitchers for each year.

Keep in mind that these numbers do not distinguish between a regular player, part-timer, or late-season call-up. The hitters or pitchers may have appeared in many games or just one game.

Also, more than 100 years ago there were a number of cases of teams folding during the season so I wonder if the numbers there contain some errors--I would put less faith in the early part of the graph than I would the post-1900 numbers.

Comments and observations:

  • In 2009, teams averaged 22 pitchers and 38 1/2 hitters per season. As you can see, these numbers are way up from historical values. In the 1880s, teams averaged about 4 pitchers and 15 hitters per season. (How mind-blowing is that?) Even as recently as the 1950s and 1960s, numbers were steady at lower values: 15 pitchers and 35 hitters per year.
  • Note that the number of hitters took a huge dip in 1973. This is due to the introduction of the DH, meaning AL pitchers no longer batted and disappeared from the list of AL hitters. In 1997, when interleague play came along, the numbers went right back up. If I showed this same plot broken out by league, you'd see that the drop 1973-1996 was entirely in the AL.
  • There are no significant differences between the NL and the AL for the pitchers per team plot.
  • A few other blips on the graph are easily explained: The 1946 and 1955 blips were due to players coming back from WWII and the Korean War, respectively. The drop down in 1994 was due to the strike that wiped out September call-ups.
  • Note that the ratio of hitters to pitchers has gradually declined over the years. In the 1920s, teams used about 2.5 times as many hitters as pitchers. By the late 1970s, the ratio dropped to 2-to-1. In the last couple of years, it's down to about 1.8. The advantage of looking at this ratio is that it tends to eliminate effects such as strikes, wars, and other things that affected games played across the league. The ratio tells us something about how teams use pitchers vs hitters. I suspect that the drop in the ratio comes down mainly to the fact that teams carry more pitchers these days. In the 1980s, most teams carried 9 or 10 pitchers on their staff. Nowadays, most teams carry 12 or 13 pitchers. More pitchers means more injuries and more replacements from the minors--in other words it seems to take 22 pitchers to occupy 12 spots over the entire season whereas it used to take only 16 to occupy 10 spots.

This entry was posted on Thursday, June 24th, 2010 at 7:57 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

9 Responses to “Average number of players used per team”

  1. Detroit Michael Says:

    It might be more illuminating to graph the number of batters when one excludes those batters who were pitchers in 75% or more of their games for the season. A similar adjustment for the pitchers would eliminate the occasional position player who pitches once or twice in a season. Otherwise, it seems there is a lot of noise in the data.

  2. Johnny Twisto Says:

    The Korean War ended in '53, and there weren't so many players drafted that they and their replacements would be crowding up the rosters when they returned. That blip actually appears to be 1956, anyway. It is rather striking, so there must be an explanation, but I am not sure what it is.

  3. Johnny Twisto Says:

    Never mind, I was counting dots in the wrong decade, it is 1955.

  4. Johnny Twisto Says:

    The '55 increase appears to be far more in the AL than the NL.

    It's the year the A's moved, and one year after the Orioles moved. Any connection? Don't know what it would be. But those two teams used a lot more players and pitchers than the rest of the league.

  5. Mariner Mike Says:

    RE: 1955 A's & Orioles. Those two clubs were pretty bad.

    I wonder if there is a correlation between team performance and the quantity of players used. It often seems that bad teams tend to make a lot of roster moves in search of players who can actually perform.

  6. Johnny Twisto Says:

    I'm sure that's probably true. But there are bad teams every year. Those teams weren't historically bad so that they should account for a noticeable spike in the graph. I don't know, it would probably require a closer look at the # of players used by each team in the surrounding seasons to make sense of.

    Well...I can never let things rest. In '53, '54, '56, and '57, it looks like 8 AL teams total used at least 40 players in a season. In '55 alone, all 8 teams used at least 40, and BAL and KCA were both over 50. So everyone was using at least a few more players, and those two were really off the charts, relatively. Still not sure why. Maybe there is no answer, it's just a freak occurrence.

    Could it have something to do with the Bonus Baby rules? Still don't know why '55 would be any different in that regard than any other year though.

  7. Two of the factors which may drive the steady increase - transportation and money. During the era of passenger trains, getting from Texas to St. Louis (or from Los Angeles to Chicago) to make the leap from Triple A to the majors took days rather than hours. Now we hear tales of young players playing in a minor league game one day and a major league game the next (sometimes being sent back out the following day), and do not think that unusual.

    And the new era of big money means that MLB teams are more likely to DL a player for a minor injury and call up a replacement without thinking twice about the cost - too much is at stake. Suspect the number of player/days on the DL has a direct correlation to this chart.

    Wonder if the wealthier teams in the 30s and 40s keep a few players close at hand as a "taxi squad"..... and need to take a closer look at the AL in '55!

  8. What about the blip in 1912-13? What explains why teams were using so many batters and pitchers in those two years, compared to any of the other years from that period?

  9. @8
    Good question. The Federal League years were 1914-1915. I can imagine several reasons why there would be a blip before the FL and a trough during and after, but I can't find any evidence online of a any roster-rule changes.