Swanson was removed from Wednesday's game at the New York Mets in the sixth inning and did not play in Thursday's trip finale. He is hitting .298 with two homers and 13 RBIs but just .171 in his past 35 at-bats.
"It's just something he's been fighting," manager Brian Snitker said Friday. "But he's handled it and managed it. It was pretty evident to me in the at-bat that it wasn't going well. I didn't want to take any chances with it."