Strop (hamstring) estimated his chances at being ready for Opening Day at 99.99 percent Wednesday, Jesse Rogers of ESPN.com reports.
An MRI on Monday revealed a mild right hamstring strain. He'll take a break from throwing off a mound but won't be shut down completely. If his optimism turns out to be unfounded, Carl Edwards and Steve Cishek will battle for closing duties, with Brandon Morrow (elbow) out for all of April.