During his pregame meeting with reporters, manager Dusty Baker said that Arroyo had his rotator cuff repaired during the same time he had Tommy John surgery in 2014. Arroyo was in uniform on Thursday and was seen talking to his teammates.
"[The shoulder] is not doing good. If it was, I wouldn't have the MRI," Arroyo said. "[The doctor said the rotator cuff] is significantly torn. ... We are going to compare the MRI from 2014 to this one, just to make sure. I'm still really strong in a lot of positions, which I wasn't last time it was hurting. So we'll see if it might be something we could calm down and maybe try to rehab.
"But it's probably going to be a long shot at this point. We're just going to take a couple days to really look at it, let them analyze between the two comparisons and see if it's the end of the game for me or not."
Arroyo was competing with right-handers Tanner Roark and Joe Ross for the final two spots in the rotation, and it looked like he had a good chance of making the team. In his most recent start, last Thursday against the Astros, Arroyo pitched three shutout innings and struck out three. Arroyo now says he wasn't healthy in that game against Houston.
Arroyo hasn't pitched in a Major League game since June 15, 2014, after undergoing Tommy John elbow surgery.
"Yeah, I haven't really been healthy since I had the surgery. I had the Tommy John [on my] elbow, and I had my rotator cuff repaired as well. It had a small tear, about 30 percent, in '14. I mean, there would be days where I felt pretty good. But it was one of those things where I couldn't tell if it was just something that would work itself out in camp as I was building up, and it would get stronger and better, or if it was something that was just going to be there all the time.
"If it stayed where it was, I could pitch with that. But it got to the point my last outing where it's just significantly so much pain that there's just no way to possibly pitch. And there's also no way to turn it around and pitch again. It's not looking real good, but we'll take a couple days to just let them analyze it a little bit."
Arroyo has had a productive career in the big leagues. He has won 145 games and posted a career 4.19 ERA in 15 seasons. He is best remembered for helping the Red Sox win the World Series in 2004 -- their first in 86 years.
Baker persuaded Arroyo to sign with the Nationals instead of the Reds this past offseason. The two were together for six years with Cincinnati.