Yankees manager Aaron Boone said Sunday that Stanton was hurt running out an infield single in the second inning of Game 1 a night earlier. Stanton remained in the game and homered off Zack Greinke in a 7-0 New York victory.
Stanton had an MRI that revealed the strain. Boone says Stanton is available to pinch hit and could start again later in the series.
Cameron Maybin was set to play left field and bat seventh in place of the 2017 NL MVP.