PHOENIX -- Friday was going to be the day that Corbin Burnes officially started his rehab assignment, which would have included a game in the Arizona Complex League. It was a date he had circled on his calendar.
All that changed, though, after facing live hitters in a batting practice session on May 29, when Burnes felt a cramp-like feeling where his teres major was. At the time, Burnes didn't think anything of it. After all, it was the elbow that had undergone Tommy John surgery, and he didn't have any issues there.
"Other than that, live hitters went really well," Burnes said. "Threw a lot of strikes, shapes were good, velocity was good. Basically, [the training staff] asked how it went, I said it felt good. There was maybe one or two pitches I felt like I couldn't let it go, felt like it was almost like a cramp or something back there, but nothing alarming."
Burnes played catch on Monday and the training staff asked if he was ready to really "step on it" for 25 pitches in Tuesday's scheduled bullpen session.
The right-hander hesitated, and though he is claustrophobic and hates the MRI tube, he suggested maybe they should get an MRI just to make sure everything was OK.
It wasn't.
Burnes was diagnosed with a strain of the teres major muscle and it is likely to delay his return to the active roster from around the All-Star break to September.
After months and months of playing catch and throwing bullpens, Burnes saw the light at the end of the tunnel. Now it's back to square one in some respects, and it was a tough pill for him to swallow at first.
"I'm doing better [mentally] today," Burnes said on Thursday. "Obviously, the last couple days have been tough. Literally, [Friday] I was supposed to go out on rehab assignment, so it's tough to have put in work for 11 months and you're a little over a month away from being back. It's tough. We worked hard to put ourselves kind of at the very front end of the Tommy John rehab. We're, gosh, probably a month and a half, two months ahead of a lot of people that come back from this."
Burnes had been pushing hard during his rehab to return as soon as possible, but he did not think that had anything to do with the teres major injury.
"I think it's more just the time we had off from competitive action, and the minute I got a hitter in the box, the intensity kind of crept up, and the tissues just weren't ready for it," Burnes said. "Elbow was great. Elbow is still great. We're completely over that now. So, when we do get to start throwing again, there's not going to be any hesitation as far as a longer build up or anything because of the elbow. The elbow, it's in the past, it's in the clear. So, now it's just getting that shoulder right and getting back."
Burnes will not throw for a bit as he waits for the shoulder to heal, but rest assured as soon as he can pick up a baseball again, he's going to do everything he can to beat the expected September timeline.
"I'm gonna push it as much as I can," Burnes said.