Masahiro Tanaka pitched five scoreless innings in an instructional game for the New York Yankees on Monday at the team's Florida pre-season training facility.
The 25-year-old Japanese star has been sidelined from Major League Baseball since early July with a partially torn ulnar collateral ligament in his right elbow.
Tanaka threw 65 pitches against a group of minor-league batters, surrendering six hits while striking out four.
Yankees manager Joe Girardi and pitching coach Larry Rothschild both watched Tanaka, as the Yankees were in the area to begin a three-game series against the Tampa Bay Rays.
The Yankees had been targeting a return for Tanaka before the conclusion of the regular season, a comeback effort that could come as quickly as next weekend.
Tanaka went 24-0 with the Japan Series champion Rakuten Golden Eagles last year before signing a seven-year deal worth $155 million with the Yankees in January.
Tanaka went 12-4 with a 2.51 earned-run average over his first 18 North American starts.