| Masa Kobayashi | |
| Position: | Relief pitcher / Pitching coach |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 24 May 1974 |
| Birth Place: | Ōtsuki, Japan |
| Debutleague: | NPB |
| Debutdate: | April 7 |
| Debutyear: | 1999 |
| Debutteam: | Chiba Lotte Marines |
| Debut2league: | MLB |
| Debut2date: | April 2 |
| Debut2year: | 2008 |
| Debut2team: | Cleveland Indians |
| Finalleague: | MLB |
| Finaldate: | May 7 |
| Finalyear: | 2009 |
| Finalteam: | Cleveland Indians |
| Final2league: | NPB |
| Final2date: | April 30 |
| Final2year: | 2011 |
| Final2team: | Orix Buffaloes |
| Stat2league: | MLB |
| Stat21label: | Win–loss record |
| Stat21value: | 4–5 |
| Stat22label: | Earned run average |
| Stat22value: | 5.10 |
| Stat23label: | Saves |
| Stat23value: | 6 |
| Statleague: | NPB |
| Stat1label: | Win–loss record |
| Stat1value: | 36–34 |
| Stat2label: | Earned run average |
| Stat2value: | 2.93 |
| Stat3label: | Saves |
| Stat3value: | 228 |
| Teams: | As player
As coach
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| Highlights: |
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is a former professional baseball pitcher and pitching coach.
From to, Kobayashi played in the Nippon Professional Baseball league for the Chiba Lotte Marines. From to, he played for Major League Baseball's Cleveland Indians. He was a member of the Japanese Olympic baseball team for the 2004 Summer Olympics and won a bronze medal.
Kobayashi led the Pacific League in saves in 2005, with 29.[1] He earned his 200th career save in 2006, becoming the third player in Japanese baseball to reach the mark, after Kazuhiro Sasaki and Shingo Takatsu.[2] In 2007, his final season with the Marines, Kobayashi finished 2–7 with 27 saves and a 3.61 ERA in 49 relief appearances.[3] He became the only Japanese professional pitcher to record 20 or more saves seven straight years.[4]
On November 2,, Kobayashi declared free agency and expressed his interest in playing for a major league club for the 2008 season. On November 20, Kobayashi signed a two-year, $6.25 million deal with the Cleveland Indians. The deal included a $3.25 million club option for a third year.
During the 2008 season, Kobayashi had an average season, going 4–5 with six saves and a 4.53 ERA in 57 relief appearances.[5] He had a 3.05 ERA in the first half, but regressed in the second half, posting a 10.32 ERA in 15 games after the All-Star break.[6]
In 2009, Kobayashi made 10 appearances (innings) with no decisions or saves, and an ERA of 8.38. On May 16, he was removed from Cleveland's 40-man roster.[7] He later cleared waivers and accepted an assignment to the Triple-A Columbus Clippers.[8] He was released on July 18, 2009.[9]
Kobayashi signed a one-year contract with the Yomiuri Giants for the 2009 season.[10] He made 16 appearances with the Giants, posting a 2.25 ERA. He later joined the Orix Buffaloes for the 2011 season.