Bronson Arroyo. (Katherine Frey/The Washington Post)

VIERA, Fla. — After days of contradictory diagnoses, including a torn labrum and a torn rotator cuff, Bronson Arroyo’s shoulder injury isn’t as serious as previously thought. He will rehab for four to six weeks in his final shot at pitching in the major leagues before calling it a career.

“It isn’t often that you get a really bad prognosis and call 30 of your really closest friends and tell them, ‘Man, I got check-mated today and I’m taking it to the house,'” Bronson said. “And then, a couple days later they tell you, ‘Maybe you got a chance.’ It’s like Forrest Gump.”

Arroyo has no issue with the bursa sac in his right shoulder, Nationals General Manager Mike Rizzo said. The Nationals compared Arroyo’s MRI from this week to one done with the Diamondbacks in 2014. Doctors found that Arroyo had partial tears of his rotator cuff tendons, which were similar to the MRI two years ago, Rizzo said. But the tendons are “extremely inflamed” and causing pain, Rizzo said.

“The remainder of the shoulder is essentially normal, as they were in 2014,” Rizzo said.

So, according to Rizzo, Arroyo will be shut down for 10-14 days. Then the 39-year-old will start a strengthening and throwing program before being re-evaluated. Rizzo estimated the process could take four to six weeks. Arroyo said there is “some damage” to his shoulder but not nearly as bad as the original prognosis.

“It’s still gonna be a coin toss if it’ll hold up to the pounding of pitching or not,” Arroyo said. “But I knew that coming in here and this is kind of a setback. I’d love to help this ball club, even if it’s in the second two-thirds of the season or at any point.”

Earlier this week, reported — and a person familiar with the situation confirmed — that Arroyo had a torn labrum. A day later, Arroyo said that his labrum was fine but he was told that his rotator cuff was “significantly torn.” On Friday, Fox Sports reported — and another person familiar with the situation confirmed — that Arroyo’s shoulder wasn’t torn. Arroyo had said earlier in the week that the MRI was read by a non-baseball doctor. Fox Sports reported that the MRI was misread and Arroyo had a bursa sac issue. Rizzo disputed that.

“The report that we misread the MRI is inaccurate,” Rizzo said. “It was misreported, by whoever reported it. The MRI was accurately reported. We did not make a comment on it because we were waiting for the 2014 MRI and surgical report. Once we got that, we assessed it with our medical staff.”

Arroyo, one of the most durable and consistent starters in recent history, is prepared to give rehab a shot. He underwent rotator cuff surgery in 2014 along with Tommy John surgery and has been out of baseball since. He came to Washington to be with his former Cincinnati manager, Dusty Baker, and compete for a final spot in the rotation. Although he never relied on velocity, Arroyo was clocked at only 84 mph in his first spring training start. After his second start, Arroyo felt so much pain he had to be scratched before a third one.

“I’m not getting cut on again,” Arroyo said. “It’s either gonna go now or it won’t. Two months is no big deal. I could even deal with it the rest of the season if I could pitch again. I just don’t want to get cut on again. The surgery, after that, it was 14-15 months of a lot of pain and not having the ability to throw a ball. You just couldn’t see the light at the end of a tunnel. That’s too much. If they went in there, it’d be two surgeries and I’ll be 40 and haven’t pitched in almost three years. I don’t think anyone would give me an opportunity.”

The Nationals will proceed with a rotation that includes Tanner Roark and Joe Ross. But if Arroyo is able to rehab and pitch effectively, he could be useful depth should injuries arise.

“Bronson is going to have an effect on this team before the season is out and we’re going to need Bronson,” Baker said.

>>> Saturday’s game was delayed and then canceled because of rain. Tickets can be exchanged for later games, with the exception of March 23 against the Yankees.

Ross was slated to start Saturday’s game but now it is unclear if he will pitch Sunday. Before the game, Baker was unsure what the Nationals would do with the pitching schedule if it rained. The Nationals have not yet announced an adjusted pitching schedule. The Nationals will play the Tigers in Lakeland, Fla. on Sunday.

>>> Baker said he doesn’t know when Gio Gonzalez will return from Washington following the birth of his first son. Gonzalez left Thursday to be with his fiancee. Baker said Gonzalez will get as much time as he needs but expects him to throw while he’s away.

>>> The Nationals reassigned Jason Martinson to minor league camp and granted Logan Schafer his unconditional release.