Nationals starting pitcher Stephen Strasburg left Saturday's game against the Giants after suffering an apparent injury in the fourth inning, per the Washington Post.
Strasburg left the game after throwing 3 2/3 innings, with what is being described as tightness in his side.
Strasburg (5-5) has a 5.16 ERA with 63 strikeouts and 18 walks in 61 innings this season. His next start is scheduled for Friday in Baltimore, but it is not known if he is in danger of missing that start.
"We will continue to evaluate his left side and see how he is tomorrow," manager Matt Williams said, per MLB.com. "Given his season, so far, I don't want to take a chance there."
Strasburg has already missed time with a variety of injuries this season, including a stay on the disabled list with a neck injury.