Jesse Carlson, the Blue Jays middle relief pitcher, said he played the second half of last season with a torn pectoral muscle in his chest which may explain the struggles he endured on the mound.
Carlson, a left-hander, said it could have been worse as the injury was to the right side of his chest.
He said he suffered the injury working out with Bryan King, the Blue Jays strength and conditioning coach.
"Two days later I'm sitting in the bullpen, it just felt like I had a knife up my arm," Carlson said from the Toronto Blue Jays spring training camp Tuesday morning. "It was bad."
It wasn't bad enough to take any time off, said Carlson, who for the second consecutive season led the team with 73 appearances.
But he wouldn't come right out and blame the injury for an inconsistent year in which his earned-run-average rose to 4.66 from 2.25 in 2008.
"I'm not going to say it did, I'm not going to say it didn't," Carlson said. "It was uncomfortable on a daily basis. Obviously when I was out there pitching I didn't think about it.
"But throughout the day and when I was done it was definitely sore. I was getting treatment for it every day and it just never went away."
Carlson said he rested the chest during the off-season and here at the Blue Jays came said he feels no pain in the chest area.
"So far so good," he said.