Gausman, who received a cortisone injection on Sunday, had been getting treatment for a while prior to that. He said things got "significantly better" but never to the point where it went away totally, which is why he took the shot.
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"Even last season, I dealt with [tendinitis]. Coming back from the DL [in May], I still had some issues with feeling fresh all the time," Gausman said. "That was frustrating, because throughout my whole career, I never had shoulder problems. And even in 2014, I felt great every time I took the mound. So last year was the first year that I realized those old guys aren't lying when they say, 'I'm a little banged up.' It was one of those things, I took notes watching other guys' bullpens and had to really take it easy some days.
"I think if it was during the season, I would probably just pitch through it and take a couple days off that I normally wouldn't. But right now it's only March 22, so I'd rather get rid of it right now than have to go into the season's first start wondering how I'm going to feel."
The Orioles have an off-day on April 5, meaning they could go without a fifth starter until April 10. If they think Gausman could be ready by then, they will hold off on placing him on the DL, a move that would backdate to March 25.
Manager Buck Showalter said the team has not decided on a contingency plan.
"I don't think we're going to have that decision to make," Showalter said. "I think Gaus will make it."
Gausman entered camp this year in great shape, having employed the use of a personal trainer for the first time. He pitched two scoreless innings in his spring debut but allowed three runs over four innings in his most recent outing, on March 16.
Gausman dealt with a similar issue last spring but wasn't sure what caused the tightness because he had never experienced it.
"I didn't really know what it was, so I just thought it would go away," he said. "And I went into the season, and I think pitching out of the bullpen -- not knowing when you're pitching, coming in and trying to throw as hard as I could -- just kind of didn't really help it. So that's one of the reasons why I went on the DL. Now, knowing what it feels like and all that, I'm just happy that I said something, happy that it's March 22 and I'm already two days into [the shot]."
Gausman will take four days off and is hoping to be able to play light catch by the end of the week. That will all depend on how he feels, of course.
"The unfortunate thing is, I'll probably have to be stretched back out, have multiple bullpens. Go back to throwing 25 pitches, kind of work up from there," he said. "That's something that's going to take more time than anything. Right now I'm just hoping I can knock it out and come back with no inflammation and no soreness."
"I think that's the first injection he's ever had," Showalter said. "There's some uncharted territory for him because he's never had any problems before, so he doesn't have anything to measure it against from the past."