Diamondbacks right-hander Corbin Burnes has suffered a teres major strain and will be shut down from his throwing progression. Manager Torey Lovullo says Burnes probably won’t be back until September with this setback. Nick Piecoro of The Arizona Republic was among those to relay the news.

The righty underwent Tommy John surgery in June of last year. That procedure normally comes with a recovery period of 14 months or longer, which would have put Burnes in line for a return in August. He was optimistic about beating that, telling reporters in February that he expected he could return around the All-Star break in July. He faced live hitters last week, per Piecoro, but any hope of a July return is now dashed.

It’s an unfortunate development for Burnes and the Diamondbacks, as both parties were hoping he could be a late-season factor. Lovullo didn’t rule him out for the season but he now has an even tighter window to make an impact on the 2026 season.

Arizona will continue with a starting five of Merrill Kelly, Zac Gallen, Michael Soroka, Eduardo Rodriguez and Ryne Nelson. It hasn’t been a great group overall but has been one of the better rotations in the National League over the past month. All aside from Gallen have pitched well of late, but Soroka is the only one missing bats at an average or better rate. Nelson has also worked around one of the highest home run rates in MLB.

It feels fairly tenuous and there’s very little in terms of rotation depth. Prospects Mitch Bratt, Kohl Drake and Dylan Ray are all on the 40-man roster and at Triple-A Reno. None of those three have pitched in MLB, and only Drake (who has an ERA above 8.00) is currently healthy. There’s not much to be done right now beyond hoping the rest of the rotation stays healthy. Arizona is four games above .500 and currently holds the NL’s final Wild Card spot. If they can hang in the postseason picture, adding a starter at the deadline feels like a must.

This also all but ensures what already looked like an obvious call for Burnes not to opt out of the remaining four years and $140MM on his six-year free agent deal. There was an outside chance Burnes could’ve considered that if he made a seamless return from the elbow surgery and dominated in the second half — especially with a dismal free agent class after Tarik Skubal. That’s not going to happen anymore. Gallen and Soroka are impending free agents (the latter after his mutual option is bought out), so the D-Backs will need a healthy Burnes in 2027.