"He's got some right knee soreness," Kapler said. "He's going to be just fine, but that was precautionary as well. It was really kind of messy conditions out there. I just wanted to get him out of there to be cautious."
Alfaro doubled and walked in his two plate appearances before he was replaced by Andrew Knapp in the middle of the fifth. He will be re-evaluated on Saturday.
Joe Harris is a contributor to MLB.com based in St. Louis.