DeRosa, hitless in nine at-bats since being acquired from the Indians in a trade, says he felt a "little tweak" while swinging and missing Randy Johnson's changeup before striking out during his second at-bat in the fourth. He hit off a tee indoors the next inning and "it just didn't feel right."
He left the game for a pinch hitter in the sixth inning.
DeRosa said he expected to have tests done on his wrist Wednesday.
Manager Tony La Russa said DeRosa may have a sprain.