Narveson returned from the 15-day disabled list to start the game. He landed on the DL earlier this month after accidentally slicing his left thumb with a pair of scissors while repairing his glove.
With one out in the bottom of the sixth, the southpaw was visited by head trainer Roger Caplinger after throwing a 1-0 fastball to Steve Pearce.
He was removed with an apparent blister on the middle finger of his throwing hand.
Narveson left with a 2-0 lead. He allowed five hits while striking out one over 5 1/3 innings and added a two-run single in the fourth.