TAMPA, Fla. -- Casey Janssen received an unwelcome reminder of where he was at this time last year during a brief outing against the Yankees on Thursday. The Blue Jays pitcher exited his start after feeling tightness in his right shoulder, the same one that was surgically repaired a year and one day ago.

Janssen does not believe the issue is serious, but it will likely be extremely difficult for him to remain a legitimate contender for a rotation job now. On Friday, Janssen will be examined by one of Toronto's team doctors to determine the extent of the injury, which the right-hander said was unrelated to the shoulder problem that came up last spring.

"It was just a weird day," Janssen said. "It's the anniversary of my surgery. I don't think it's a very good day."

A year ago, Janssen flew to California and had Dr. Lewis Yocum perform an operation to repair a tear of the labrum in the pitcher's throwing shoulder on March 18. Janssen said the source of the tightness he experienced this time around was not located near the sharp pain he felt in his shoulder last spring.

"No trigger points were the same," the righty said. "It's a completely new spot, which I think is a good thing. I feel fine. It's just tight."

Janssen said this latest injury involved the lateral muscles behind his right shoulder, adding that he was able to successfully work through a series of manual tests given by Toronto's medical staff. The 27-year-old hurler said he first felt the stiffness in his arm while warming up in the bullpen at George M. Steinbrenner Field.

The discomfort persisted after Janssen took the mound in the first inning. After retiring the leadoff hitter, Janssen walked two batters and allowed a base hit. Following a one-out walk to New York's Hideki Matsui to load the bases, Jays pitching coach Brad Arnsberg jogged out to the mound to talk things over with Janssen, who promptly retreated to the training room.

"I was not throwing hard and just trying to hopefully work through the soreness," Janssen said. "It just didn't go away. I think you could kind of tell and it just made sense to get me out of there."

Janssen said he believes he can recover quickly enough to resume throwing soon, but chances are the Jays will take extra precaution with his injury, considering his health history. That will cast serious doubt on Janssen's chances at grabbing one of the two rotation vacancies. Scott Richmond, Brad Mills and Matt Clement are also in the running for the open roles.

"All my work up until today was great, so I just don't see this being much," Janssen said. "I'll see the doctor and go from there. We think we've got a pretty good idea, but you never know. I hate to say I'm not that worried. It's just a bummer that I didn't get through this outing."

Throughout Spring Training, Janssen and Richmond have been considered the frontrunners to land one of the available starting jobs. The Jays have been impressed this spring with Mills, a left-handed prospect, and Clement has displayed good health and results after coming back from right shoulder issues of his own.

Janssen's last full season with the Jays came in 2007, when he posted a 2.35 ERA and recorded 24 holds in 70 games out of the bullpen. Prior to that season, Janssen worked primarily as a starter throughout his professional career. So far this spring, Janssen has responded well to being stretched out to start again, though he admitted that he might have been pushing too hard.

"It may be overworking," Janssen said. "But, again, every test they've given me my arm has reacted great to. Maybe it's just the first little hiccup. It doesn't seem like it's going to be that bad."