Blue Jays catcher J.P. Arencibia broke his right hand on a foul tip Wednesday night and is expected to miss six weeks.
Arencibia was hit during Oakland's eight-run second inning. He finished the inning, but Jeff Mathis pinch hit for him to start the bottom half.
Arencibia is hitting .242 with 16 home runs and 50 RBI.
The injury-ravaged Blue Jays already have 10 players on the disabled list, including defending home run champion Jose Bautista (left wrist) and nine pitchers.