With one out in the fifth, Robert Andino fouled a pitch off the forehead section of Montero's mask, who immediately staggered backward. Montero knelt behind home plate and talked with a trainer and manager Eric Wedge before carefully walking off the field. Miguel Olivo replaced Montero.
"It happens, it happens to every catcher," Montero said. "It was a good impact around my face and I was feeling dizzy. They took me out just to make sure, but thank God nothing happened."
Montero admitted he still felt a bit dizzy after the game, but said he should be fine.
Wedge added that it wasn't similar to the concussion outfielder Franklin Gutierrez is dealing with that landed him on the seven-day disabled list, but Montero will be reevaluated Thursday.
The 22-year-old backstop is hitting .245 with eight home runs and 28 RBIs this season, his first with the Mariners, but is just 3-for-26 on the current homestand.