Mathis stayed in the game after being hit in the third inning. He had X-rays afterward that were negative, and the diagnosis was a bruise.
The first ruling on the play by home-plate umpire Gary Darling was that the ball had hit the bat and was a foul ball.
"I stepped out and tried to shake it off because I knew it hit my hand," Mathis said on Sunday. "Once I took my glove off it was bleeding and purple, and so he said, 'I'm going to get this call right.'"
Angels manager Mike Scioscia had come out of dugout before the call was changed. When it was ruled a hit by pitch, Blue Jays manager John Farrell argued the call.
"It started to stiffen up toward the end," Mathis said.