Woo was removed from Monday's game against the Rays due to right hamstring tightness.
Woo left his start with the team trainer after suffering what looked to be a right leg injury, and he's since been diagnosed with a hamstring issue. The team should have a better idea of whether he'll require a trip to the injured list after further evaluation, and he's set to undergo an MRI on Tuesday, per Daniel Kramer of MLB.com.