PHOENIX — Arizona Diamondbacks reliever Christian Montes De Oca will undergo lower back surgery, which jeopardizes his chances to pitch again this season, manager Torey Lovullo said on Saturday.

Montes De Oca just made his major league debut on June 7 at the Cincinnati Reds, throwing 2.2 scoreless innings.

The exact date of his surgery is to be announced.

“I think it’s a two-to-three-month recovery, so we’re looking at something that might eliminate him for the rest of the season,” Lovullo said. “But I’ll keep you posted on the timing of that.”

Before Monday’s game, Lovullo was alerted that the 25-year-old would not be available, and the club placed him on the 15-day injured list the following day for right elbow inflammation.

It turns out, his back was the bigger issue, one he tried to push through.

“ It’s something that’s been lingering, something that’s been bothering him, the way it’s been explained to me, since spring training,” Lovullo said. “Something he’s been trying to manage became a little bit too unmanageable over the past couple of weeks.”

Montes De Oca, a 6-foot-4 right-hander from the Dominican Republic, worked his way through the system since he signed at 22 years old, later than most players who sign from Latin America. In 24.1 innings with Triple-A Reno this year, he worked a 4.07 ERA with 26 strikeouts and six walks.

As an arm who could go multiple innings, Montes De Oca was an intriguing young arm for an ailing bullpen.

He remains on the 15-day IL, so Arizona can open a 40-man roster spot by transferring him to the 60-day IL when need be. The D-backs already have five pitchers on the 60-day IL.

Christian Montes De Oca snagged two strikeouts in his Major League Debut 🥹 pic.twitter.com/BTHvMy5BWv

— Reno Aces (@Aces) June 7, 2025

When will we get A.J. Puk news?

Diamondbacks reliever A.J. Puk will visit renowned surgeon Dr. Neal ElAttrache in Los Angeles sometime next week, at which point the timeline and plan will be clearer.

He stepped back from his throwing program due to some lingering discomfort in his left elbow, Lovullo said on Friday.

More details on Justin Martinez’s surgery

The work to be done on Justin Martinez’s UCL is clinically referred to as a revision, an increasingly popular procedure as second Tommy John surgeries are increasing among pitchers.

It is not a total reconstruction of the ligament.

“In J-Mart’s case, there’s a little tear in the surgically repaired — I think 2021 was the procedure — ligament that was put in there,” Lovullo said. “So, they’re gonna repair that and they’re not gonna put a new ligament in there. They’re gonna put a brace over it.”

UCL repairs with an internal brace have also become more prevalent, as the brace (made from collagen coated fiber-tape) provides structural support and could speed up recovery time. Lovullo mentioned 12-13 months as a possible timeline on an MLB Network radio appearance on Friday, which would be quicker than a potential 14-16-month absence for a reconstruction.

“It could be 12 months. It could be 13 months.”

Torey Lovullo with the latest update on Justin Martínez (UCL sprain), who is seeking a second opinion:@Dbacks | #Dbacks
🔗 https://t.co/6YbqEWFvEp pic.twitter.com/2Be7Uv5IPN

— MLB Network Radio on SiriusXM (@MLBNetworkRadio) June 13, 2025