If the test comes back and shows a tear, the Orioles will be left with two choices -- rest and rehabilitation or season-ending surgery. Patton went four months without throwing this winter, but the discomfort never really went away. He'll be examined by Dr. John Wilckens on Monday and the Orioles will decide on a course of action shortly thereafter.
"I don't know yet, I'm not going to rush to any conclusions," Patton said on Sunday. "I'm just going to go and listen to what [they] tell me. They'll tell me what I need to do and we'll go from there. We'll know a lot more tomorrow, I think."
The Orioles acquired Patton -- along with four other players -- from the Astros in exchange for shortstop Miguel Tejada in December. They knew about his injury at the time, and their doctors had access to Houston's medical file. One source said that Patton got a second opinion from outside either organization and came back with a similar diagnosis.
Patton has already undergone a standard magnetic resonance imaging test, but he said the doctors need the advanced MRI to tell whether he'll need surgery. He's steadily done all his work this spring in the hope of avoiding the operation, but he's also been frank with the media about the possibility that he'll miss most or all of the year.
"I'd like to know exactly what's going on in there, so I'm kind of anxious to see an MRI and talk to a doctor," said Patton, who's made just two big league starts. "I don't know that I'm shut down for the season or for any amount of time. I'm not frustrated at all. I've just got to see the doctor and I'll know more after the MRI or whatever he decides to do."
Patton, a ninth-round pick in the 2004 First-Year Player Draft, has a 27-28 record with a 2.99 career ERA in the Minor Leagues. The left-hander went 6-6 with a 2.99 mark for Double-A Corpus Christi and 4-2 with a 4.59 ERA for Triple-A Round Rock last season. He made it up to the Astros in September and posted an 0-2 record with a 3.55 ERA in two starts and one relief stint.
Baltimore came into Spring Training expecting Patton to battle for the fifth starter's slot, and manager Dave Trembley even tabbed him as the early favorite. In his absence, fellow southpaws Brian Burres and Garrett Olson appear to be the new favorites for the job. Other candidates include Matt Albers, Hayden Penn and Radhames Liz.
"I think I've gone on record as saying I was not opposed [to Patton]," Trembley said Sunday morning. "If he showed he could get hitters out and pitch at the Major League level, we were going to give him that opportunity. I think that's what I said, and I think we may have to move away from that depending on what we find out tomorrow from Dr. Wilckens.
"If you've been following what we've been doing, we've prepared ourselves for that. If you see how the pitching lines up over the next week or so, you'll see we've done our homework. We had Plan A and we had Plan B."
Patton said earlier this spring that he felt like he was making progress, but he said that his next two side sessions "plateaued" and left him feeling the same discomfort he felt last September with the Astros. The 22-year-old got back on the hill before Sunday's game against Washington and had to cut things short one-third of the way through.
"It was uncomfortable enough to where I didn't want to pitch," he said. "It hurt enough to where I didn't want to throw."
"We're just not breaking through," added pitching coach Rick Kranitz. "There's just no need at this point to push him."
Spencer Fordin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.