Arizona Diamondbacks pitcher Christian Montes De Oca (80) during spring training workouts at Salt River Fields at Talking Stick in Scottsdale on Feb. 15, 2024. Rob Schumacher/The Republic / USA TODAY NETWORK

D-backs Reliever Showed Potential in Lone Opportunity

Originally posted on Arizona Diamondbacks on SI
By Alex D'Agostino | Last updated Dec 23, 2025 10:00 AM ET

The Arizona Diamondbacks endured a tough year in the 2025 season. Despite coming into the year with high hopes and a roster expected to make a massive impact, Arizona ended their year 80-82, missing out on the playoffs and looking to regroup for 2026 and beyond.

It was more than simple bad luck. The D-backs went through a massive slate of critical injuries, and saw more than one key player underperform. They were forced to sell off large chunks of the roster at the Trade Deadline, and turn to a bevy of unproven or journeyman players to get through the season.

That attrition was most harshly felt on the pitching staff — particularly the bullpen.

One such young, unproven arm that was awarded an opportunity due to that fact was right-handed reliever Christian Montes De Oca — who debuted in the 2025 season before eventually going down with his own season-ending injury.

As Arizona Diamondbacks On SI breaks down each individual season from the entirety of the 2025 roster, the below article will be updated with the proper links as the season reviews are published:

Arizona Diamondbacks 2025 Player Review: Christian Montes De Oca

Alex D'Agostino

Montes De Oca had swiftly risen through the ranks of the D-backs' farm system. He was promoted from Amarillo to Reno in 2024, and began 2025 at the Triple-A level.

He was quite successful in Reno to begin his 2025 campaign, throwing to a 4.07 ERA in 24.1 innings. For the extremely offense-heavy environment, that ERA number is considered well above average.

That, coupled with his upper-90s fastball and hard slider, helped create an opportunity for the righty. He was called up to the majors on May 16, but strangely, in a week's time, was not able to get into a game.

He was optioned back on May 22, but recalled from the minors on June 7. Finally, he made his debut, and it was quite an impressive one, at that.

In the midst of a brutal road series against the Cincinnati Reds, Montes De Oca was called upon to deliver length. He did just that, pitching 2.2 innings of relief in that June 7 game. He did not allow a run or a hit, walked one, and picked up his first two big-league strikeouts.

Unfortunately, he went on the IL three days later with elbow inflammation, and would eventually miss the remainder of the year. However, it was not Tommy John Surgery that claimed 2025 for him — it was a surprise back surgery.

Christian Montes De Oca: 2026 Outlook

Montes De Oca has begun throwing and should be able to make his return in 2026. As a power arm, there is value in the 26-year-old, even if he's been outrighted off the 40-man roster.

Currently on the Reno Aces' roster, Montes De Oca could easily see the field at the MLB level again in 2026, and seemed to have the makeup of a major league-caliber arm in his very small sample size.