McClanahan will undergo an MRI on Wednesday after he was scratched ahead of his scheduled start Tuesday against the Marlins with a left shoulder impingement, Marc Topkin of the Tampa Bay Times reports.
Reliever Shawn Armstrong ended up making a three-inning spot start in the Rays' eventual 7-2 win after McClanahan experienced shoulder discomfort while warming up prior to the contest. Though manager Kevin Cash said he's "optimistic" that McClanahan won't miss extended time after receiving the initial diagnosis of an impingement, the MRI will reveal whether or not a more serious injury is in play. Even if the impingement is confirmed, Topkin posits that McClanahan will likely require a cortisone shot for his shoulder and could need two weeks to make a full recovery before slotting back into the rotation. With that in mind, expect McClanahan to land on the 15-day injured list within the next day or two.