Perez was pulled from Friday's game against the Dodgers due to right knee discomfort.
Perez hit a three-run homer in the fourth inning to give Kansas City a 3-0 lead, but his knee caused him to come out of the game during the eighth. It's unclear how severe the backstop's injury is, but the Royals should know more before Saturday's contest. If he does have to miss any amount of time, Freddy Fermin would be the next man up as Kansas City's main catcher.