Felipe Vazquez is being examined for left forearm discomfort, director of sports medicine Todd Tomczyk said.
Vazquez noted the pain in the last two pitches of his appearance Sunday against the St. Louis Cardinals.
Vazquez allowed three inherited runners to score on two walks and a hit.
Tomczyk said Vazquez has not experienced that type of issue with the Pirates before.
Vazquez was not available for an interview after Sunday’s loss.
Elizabeth Bloom: ebloom@post-gazette.com, 412-263-1750 and Twitter @BloomPG.