Jason attended
Tarkington High School in Cleveland, Texas. He was selected 10th round (252nd overall) by the
Philadelphia Phillies of the 1985 June amateur Baseball draft. Like many relief pitchers, Grimsley began his career as a
starting pitcher. But he became a full-time reliever while a member of the Yankees.
Philadelphia Phillies (1989–1991) Grimsley began his career in 1989 and surrendered 13 runs in 18 innings. The following year, he went 3–2 and made 11 starts. In 1991, Grimsley went 1–7 with a 4.87 ERA in 12 starts. Following the 1991 season, he was traded to the
Houston Astros for
Curt Schilling.
Out of the league and Cleveland Indians (1992–1995) Grimsley spent the entire 1992 season in the minors and on March 30, 1993, was released by Houston and signed with the Cleveland Indians. In his first season with Cleveland, he went 3–4 over 10 games, and in 1994, went 5–2 with a 4.57 ERA in 14 games. Grimsley is known for his leading role in the
1994 Bat Burglary involving
Albert Belle and an allegedly
corked bat that was taken away by umpires for examination by the league. Grimsley was the player who crawled through a
Comiskey Park air conditioning duct to reach the room where the confiscated bat had been secured. He took the corked bat and replaced it with a clean bat. Not accounted for in this plan, however, was the fact that Belle's bat had his name on it, and the replacement had teammate
Paul Sorrento's name on it instead, leading to the heist being caught before the end of the day. The incident made ESPN.com's "Biggest Cheaters in Baseball" list at number 4. The next season, Grimsley was used mostly as a reliever, making only two starts. Following the season, on February 14, 1996, he was traded to the Angels.
California Angels (1996) Grimsley went 5–7 with a 6.84 ERA in 1996 while making a career-high 20 starts. On October 8, he was granted free agency.
Out of the league again (1997–1998) Grimsley signed with the Tigers on January 17, 1997, but was released following spring training. On April 3, he signed with the Brewers and on July 29, was traded to the Royals for
Jamie Brewington. Grimsley was granted free agency on October 15. On January 8, 1998, he signed with the
Cleveland Indians. Grimsley did not appear in a major league game that year and was granted free agency on October 15.
New York Yankees (1999–2000) Grimsley signed with the Yankees on January 26, 1999. With the Yankees, he rebounded, going 7–2 with a 3.60 ERA in 55 relief outings. Grimsley did not pitch in the
1999 American League Division Series or the
1999 American League Championship Series, but pitched innings of two-hit, two-walk ball in Game 3 of the
1999 World Series. In 2000, he was 3–2 with a 5.04 ERA. In the
2000 ALCS, he pitched one scoreless inning and earned his second
World Series ring when the Yankees defeated the Mets in five games despite not pitching in the World Series. On November 20, he was released by the Yankees.
Kansas City Royals (2001–2004) Grimsley signed with the Royals on January 19, 2001. In his first season in Kansas City, he was 1–5. In three and a half years in Kansas City, Grimsley never posted a record better than .500 (he was 3–3 in 2004). He was 1–5 in 2001, 4–7 in 2002, and 2–6 in 2003. Grimsley also gave up the home run to
Scott Hatteberg that gave the
Oakland Athletics their 20th straight win in 2002, as depicted in the film
Moneyball. On October 29, 2003, he was granted free agency, but re-signed on December 7. In 2004, Grimsley went 3–3 with a 3.38 ERA before being traded on June 21 to the Orioles for
Denny Bautista.
Baltimore Orioles (2004–2005) Grimsley went 2–4 in 2004 with Baltimore. In 2005, he posted a 1–3 record with a 5.73 ERA, and was granted free agency on October 27.
Arizona Diamondbacks (2006) In 2006, Grimsley finished 1–2 with a 4.88 ERA in 19 games before being released on June 7 after his use of performance-enhancing drugs came to light. He subsequently retired. ==Illicit drug use==