The Pirates removed Andrew McCutchen from the lineup Sunday because of pain in his right knee.
McCutchen approached the Pirates' coaching staff after taking batting practice Sunday morning to inform them of the discomfort.
"[He] had right knee soreness and he wasn't comfortable," manager Clint Hurdle said.
McCutchen said he thought the pain originated Thursday when he slid into home plate against the Milwaukee Brewers.
"I didn't feel anything at the time, but I think that's something that caused my uncomfortable feeling," McCutchen said.
Hurdle said the Pirates' medical staff checked McCutchen's knee and "he felt better about the situation."
"Just wanted to make sure everything was OK," McCutchen said. "I feel like I can play through whatever, but I didn't want to jeopardize the rest of the season playing through something I wasn't comfortable about."
McCutchen had started 42 of the Pirates' 43 games this season before Sunday.