Matsui batted once against Toronto right-hander Roy Halladay, grounding out to third base in the second inning at Rogers Centre and feeling his hamstring tighten up as he left the box.
Matsui was replaced in the fifth inning by pinch-hitter Nick Swisher.
"I'm not worried," Matsui said through an interpreter. "I feel like I could have stayed in the game, but they just took me out for precautionary measures."
The Yankees said Matsui is listed as day to day. He is batting .263 (26-for-99) with six doubles, one triple and 13 RBIs in 29 games for New York this season, and he assembled a 12-game hitting streak from April 18-May 2.
Yankees manager Joe Girardi said that he did not believe Matsui strained the hamstring, and that head trainer Gene Monahan would be able to deliver a better report on Wednesday. No MRI exams were planned as of Tuesday night.
"I won't really have any idea until tomorrow," Girardi said. "Maybe he'll be OK tomorrow. But there was tightness in there, and you throw that in with his knee and it's a risky proposition."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.