Betts’ leg bent awkwardly as the All-Star outfielder slid into Orioles catcher Chance Sisco while attempting to avoid a tag in the bottom of the first inning.
Betts limped back to the dugout and, after high-fiving several teammates, went down the steps into the Red Sox clubhouse with trainers. He initially stayed in the game and had another at-bat in the second inning before being replaced by Blake Swihart before the top of the fourth.
The Red Sox have not officially given a reason for Betts’ early exit from the game.
Betts, 25, is off to an outstanding start this season for the Red Sox, batting .353 with two home runs and 10 RBIs in 14 games.