The MRI most likely will take place on Monday while the Orioles open a three-game series against the Blue Jays at Rogers Centre.
Tillman lasted only three innings today before manager Buck Showalter, concerned by a drop in his starter's velocity, summoned left-hander Randy Wolf from the bullpen.
Tillman said the elbow felt "achy and dead," and that it's happened a few times before in his career. He doesn't seem concerned about it, but the MRI will be done as a precaution.
"It started barking on me a little bit and I felt OK, but at the same time you don't want to push anything and make it worse," he said. "I'd like to keep going, but at the same time, the team doesn't deserve someone out there that's not going to be able to throw 100 percent.
"I wouldn't say it's a pain. It's more dead. It just feels achy and dead. I've dealt with it before in bullpens and you kind of manage it and kind of get your work in. But during a start, you've got to go out there and give it your best. It's one of those things where you don't want to make it worse. I'll go get it checked out just in case."
The discomfort surfaced right from the start, Tillman said, "and it continued to get a little tighter on me, but that's the way it goes."
Asked if his condition could keep him out of the rotation, Tillman replied, "I personally don't. We did a couple tests with the trainers and they said it looked really good, but I'll head to Baltimore tonight and get an MRI hopefully tomorrow. It's just kind of a 'just in case' thing.
"It's unfortunate. I felt like I let my team down there a little bit, not being able to get deep in the game, but Randy (Wolf) came in and picked me up.
"It was huge, it was big. I was kind of down on my self coming out of that game, but Randy picked me up huge, and what a series Mark (Reynolds) had. That was fun to watch. I'm just glad we got the win today."