Pittsburgh Pirates right-hander Hunter Stratton exited Thursday afternoon's game against the St. Louis Cardinals in the eighth inning due to an apparent arm injury.

Stratton took over for fellow reliever Justin Bruihl to start the eighth and struck out Nolan Arenado to begin the frame. After throwing his second pitch to the next batter, Brendan Donovan, Stratton motioned toward the dugout and called for a trainer.

A brief discussion on the mound ensued, and Stratton was removed from the game. Right-hander Dennis Santana took over in his Pirates debut.

Including Thursday's abbreviated appearance, Stratton is 2-1 with a 4.26 ERA this season. He has come out of the bullpen in 29 games.

Pittsburgh trailed 4-3 at the time of Stratton's departure.