Casey Janssen thrived after he took over as Toronto Blue Jays closer last season. He was successful on 22-of-25 save attempts while posting a 2.54 ERA for the season.

But by October, he knew something wasn't quite right with his right arm.

"I was grinding through the end of the year," Janssen said.

His numbers declined in September and twice he went at least four days between appearances.

Janssen hoped all he needed would be rest, but by mid-November his shoulder still wasn't feeling right and he had surgery to shave his collarbone (clavicle) in an effort to relieve the discomfort. Janssen says the procedure, compared to "most arm surgeries," is considered "very minor."

But as Blue Jays pitchers and catchers participated in their first official workout Wednesday, Janssen admitted he isn't 100 percent. He is scheduled to throw his first bullpen session Thursday and, if all goes well, he expects to be full-go well before opening day.

"Am I a little bit behind? Yes," Janssen says. "Have I always been a couple of weeks early, chomping at the bit to get out of spring training? Yes. Now I'm going to be ready right at the end of camp instead of 10 to 14 days earlier and going nuts from wanting to get out of it."

If Janssen has a setback, the Blue Jays will turn to Sergio Santos, but he is returning from season-ending shoulder surgery. Santos began last season as the Jays' closer but pitched only six times before a shoulder injury shut him down and required a "general cleanout" in late July.