Washington Nationals right-hander Max Scherzer was scratched from his start at Baltimore on Saturday night due to mild discomfort in his right triceps, according to the team.
Jon Lester will start in his place.
This isn't Scherzer's first setback this season. He spent time on the injured list last month with a groin injury.
Scherzer is 7-4 with a 2.83 ERA this season. He is fourth in the National League with 142 strikeouts.