John Edwin Semprini
- Bats Right, Throws Right
- Height 6' 3", Weight 195 lb.
- School Des Moines Area Community College
- High School Dayton High School
- Born February 27, 1959 in Dayton, IA USA
Selected in the 9th round of the 1979 amateur draft. In rookie ball Semprini was 2-2 with a 5.14 ERA in 42 innings of work (16 games, three starts). He allowed 51 hits, 28 walks and he struck out only 21 batters. The following season, Semprini played for both the Macon Peaches and Lynchburg Mets, going a combined 1-6 with a 2.34 ERA in 23 games (six starts). In 1981, he split time between the Jackson Mets and Tidewater Tides, going 7-5 with a 2.31 ERA in 48 relief appearances. He saved 14 games and struck out 88 batters in 74 innings of work. He won the Rolaids Relief Pitcher of the year in the Texas League in 1981, He spent the entire 1982 season with the Jackson Mets, going 4-2 with a 3.22 ERA in 43 relief appearances. In 1983, he split the season between the Jackson Mets and Tides again, going a combined 3-2 with a 3.86 ERA in 46 relief appearances.
On January 5, 1984, Semprini was sent to the Mariners for Jim Maler. He spent one year in their system, going 2-2 with a 4.38 ERA in 41 relief appearances. He played for the Chattanooga Lookouts and Salt Lake City Gulls.
Overall, Semprini went 19-19 with a 3.41 ERA in 217 career appearances (9 starts).