Mariners rookie catcher Jesus Montero left Wednesday's game against Baltimore after taking a hard foul ball off his mask and needing to be helped off the field.

Montero was staggered and knocked backward when Robert Andino's foul ball in the fifth inning hit Montero square in the mask just above the opening for his vision. Montero was down on one knee for several minutes and was wobbly when he stood. He was helped off the field with a trainer holding his arm.

Montero was replaced by Miguel Olivo.

Seattle may be forced to use the concussion disabled list for the second time in its 10-game homestand. Center fielder Franklin Gutierrez is already on the seven-day list after a pickoff throw hit him in the face.