And it could end up being more than just a bruise.
The incident occured in his only at-bat of the game, when Guardians pitcher Tanner Bibbe threw a 3-2 fastball that caught Greene on his right leg. While it did not appear as bad initially, slow-motion replay showed the pitch caught his leg guard.
The 25-year-old took a moment after being hit, but eventually ran to first base.
Everything appeared to be fine after that as Greene ran from first base to home on an RBI double soon thereafter as Spencer Torkelson's hit gave the Tigers their first run of the contest. He did not show any signs of discomfort while sprinting around the bases.
However, Greene stayed in the third-base dugout at the beginning of the third inning, with Ben Malgeri taking his place at left field. Then, at the beginning of the sixth inning, the Tigers announced that their All-Star outfielder would not return to the game due to right hamgstring tightness and not a contusion.
"Any time you take a guy like Riley out, there is a level of concern," manager AJ Hinch said later on as his team went on to win 6-4. "But I have no idea. We will get up tomorrow and get him a test. When the lineup comes out tomorrow, he's not going to be on it. I'm not even going to consider it. But we will see what happens.
"Hopefully it's day to day."
Greene has barely missed any action for the Tigers this year, appearing in 116 of 118 games so far. The three-time All-Star is usually a designated hitter, currently hitting .273 with 16 home runs and 54 RBIs this season.