Stephen Strasburg left Tuesday night's start against the Atlanta Braves because of a tight right trapezius muscle.
Strasburg will have an MRI on Wednesday, according to Dave Martinez.
The Washington Nationals right-hander left after a comebacker by William Contreras hit him in the glove and appeared to nick his wrist. The training staff had already visited Strasburg in the bottom of the first inning after he walked Ronald Acuna, Jr. on four pitches.
Strasburg was seen shaking his right arm against Acuna and never looked comfortable during his outing, as his fastball averaged just 89.9 mph on the 11 four-seamers he threw.