Corbin Burnes set to undergo Tommy John surgery

The news is devastating but unsurprising. Burnes was pitching on Sunday when he called the training staff out from the dugout. He departed that game and the club later announced that he was experiencing elbow discomfort. He went for various medical opinions in the following days but it seems the worst-case scenario could not be avoided, so he’ll go under the knife. Given that Tommy John surgery usually requires 14 to 18 months of recovery time, Burnes is definitely out for the rest of 2025. A return in late in 2026 is possible but can’t be guaranteed.

Burnes is well known as one of the best pitchers in the sport. He won a Cy Young Award while pitching with the Brewers in 2021. He posted a 2.43 earned run average in 167 innings that year. He struck out 35.6% of opponents, only gave out walks at a 5.2% clip and got grounders on 48.8% of balls in play.

His results have backed up a bit since then but he’s still been excellent. Over the next three years, his strikeout rate continued to fall but it didn’t prevent his overall run prevention much. His ERA finished around 3.00 in each season from 2022 to 2024, even though his strikeout rate fell to 30.5%, 25.5% and 23.1% in those seasons.

He was one of the top free agents in the most recent offseason. MLBTR placed him second in the class, behind only Juan Soto, predicting Burnes could land a $200MM contract over seven years. He naturally fielded a lot of interest, with clubs such as the Orioles, Blue Jays and Giants among those who were connected to him most often.

In late December, he finally picked a new team. Arizona was a surprising destination since the club already had a number of rotation options and wasn’t heavily connected to the starting pitching market. But Burnes is an Arizona native and reportedly wanted to be close to his family, so the two sides made it work. The six-year deal guarantees Burnes $210MM, though with $64MM of that deferred into the next decade. It also affords him the opportunity to opt out after the 2026 season.

The Diamondbacks had made a number of investments in their rotation in recent years but this was the largest by far. Going into 2024, they gave Eduardo Rodríguez a four-year, $80MM deal and Jordan Montgomery also got a one-year, $25MM guarantee plus an easily-attainable vesting option.

Despite the heavy amount of investment in starting pitching, the Arizona rotation hasn’t been a strength. That was true even before this Burnes news, something that MLBTR’s Anthony Franco recently took a look at in a post for Front Office subscribers.

Losing Burnes for the rest of the year will only compound the problem. Montgomery himself required Tommy John surgery before the season started, so he’s already been out of action all year. Rodríguez has a 7.05 ERA in nine starts. He went on the IL in mid-May due to shoulder inflammation and was reinstated today.

Despite having one of the best lineups in baseball, the Arizona pitching has contributed to a fairly disappointing season so far. A recent four-game win streak has got them back to .500, but their 31-31 record still has them 3.5 games out of a playoff spot at the moment. They will have to try to climb back into the race without Burnes. Their current rotation consists of Rodríguez, Zac Gallen, Merrill Kelly, Brandon Pfaadt and Ryne Nelson. Kelly is having a good year but Gallen, Pfaadt and Rodríguez are all struggling. Nelson has been in a swing role and is only now taking up a rotation spot in the wake of the injuries.

With the club hovering around contention, decisions will have to be made about the club’s deadline plans. If they fall back in the standings, they have a number of impending free agents and could have a lot to sell. That includes Gallen, Kelly, Eugenio Suárez and Josh Naylor. Montgomery is also an impending free agent but naturally has no trade value since he’s out for the year. Though if the Snakes can hang in there, adding at the deadline could obviously be the move.

Those impending free agencies and the Burnes surgery will also lead to questions about the 2026 rotation. As of now, it consists of Pfaadt, Rodríguez and Nelson. There are some prospects who could potentially take up roles but it’s clearly a very different picture to the imperfect group they have now.

Turning to the Burnes opt-out, it now seems incredibly unlikely that he triggers it. Though he could come back late next year, that will likely be for a handful of starts at most. It would be hard for him to build up enough of a platform to turn down the four years and $140MM (with deferrals) left on the deal.

That’s a largely moot point for the future. For today, the takeaway is that it’s real bad news for the Diamondbacks. Subtracting Burnes blows a big hole in their rotation right now, while the club is trying to salvage the season, and into the long-term as well.