McClanahan experienced tightness in his left forearm during Wednesday's game against the Yankees, Marc Topkin of the Tampa Bay Times reports.
The issue arose when the southpaw was warming up ahead of the fourth, following a third inning that saw him cough up five runs on homers by Anthony Volpe and Giancarlo Stanton. McClanahan will head back to Tampa on Thursday to be checked out by the team doctor, at which point more details regarding the severity of his injury will be available. Fantasy managers should consider him day-to-day for the time being, but the Rays will be holding their breath that the team's ace isn't facing a lengthy absence.