Where Corbin Burnes leaves the D-backs’ starting rotation

The Arizona Diamondbacks had already been working from a surplus of starting pitching before adding a Cy Young winner in perhaps the most surprising offseason move in MLB.

Starter Corbin Burnes agreed to a six-year, $210 million contract with the D-backs on Friday night, the largest contract in team history, albeit with an opt-out after 2026. Co-aces Zac Gallen and Merrill Kelly, who have anchored the starting five for much of the past five seasons, and Burnes provide Arizona with one of the deepest rotations and most effective top threes in the league.

Since 2022, there have been 36 seasons put together with 184-plus innings and a 3.50 ERA or lower, and Arizona’s new trio accounted for six of them. Current D-backs starter Jordan Montgomery adds a seventh, per Stathead.

We can debate who gets the ball on Opening Day, March 27 against the Chicago Cubs later, because the more pressing question is how the front office manages having too many starters.

Entering the new year, Arizona has a starting pitcher group of:

RHP Corbin Burnes
RHP Zac Gallen
RHP Merrill Kelly
LHP Eduardo Rodriguez
RHP Brandon Pfaadt
RHP Ryne Nelson
LHP Jordan Montgomery

With young depth on the 40-man roster provided by:

LHP Tommy Henry
RHP Yilber Diaz
RHP Cristian Mena
LHP Blake Walston

Add in the return of Drey Jameson from Tommy John surgery, although it seems likely there will be more opportunities for him to contribute from the bullpen.

There is at least one trade that needs to be made here, a potential opportunity to address other areas of an 89-win team pushing hard to get back to the postseason.

Montgomery is set to make $22.5 million after opting into a player option, and the D-backs could benefit from getting off as much of that money as possible. The projected payroll after adding Burnes pushed well past last season’s club record $173 million, as Spotrac projects the D-backs’ current payroll (after arbitration) at $188.5 million.

General manager Mike Hazen mentioned earlier this offseason he expected the payroll to be similar to 2024, but situations change and unexpected opportunities present themselves throughout an offseason, such as an ace wanting to pitch closer to home.

Burnes’ contract will contain significant deferrals and won’t be a straight $35 million per year, according to Arizona Sports’ John Gambadoro. The club has needs in the bullpen and a right-handed bat, with Gambadoro reporting the team has shown interest in closers Ryan Helsley, Kirby Yates and Pete Fairbanks.

So I expect the Corbin Burnes contract to be $20 million per year in the first two years and $25 million per year in each of the following four years. Deferred payments of $60 million to begin in 2031. https://t.co/Qj0plnfsfX

— John Gambadoro (@Gambo987) December 29, 2024

Burnes is not only an effective starter (3.19 career ERA) but a dependable and durable arm who should provide value based on volume, as well.

He pitched 193 innings or more in three straight seasons.

While his strikeout rates have decreased over the years (from 36.7% in 2021 to 23.1% in 2024), he induced more ground balls and less hard contact last year while maintaining elite results with a 2.92 ERA, according to Statcast.

How will the Diamondbacks’ rotation round out behind Corbin Burnes?

Even if Montgomery is dealt, there are difficult decisions to make come spring training because the group would be six strong.

Nelson has made it difficult to overlook him after he was Arizona’s most reliable starter in the second half of 2024.

He made mechanical and mental tweaks and produced a 3.23 ERA in 11 games during the second half. That earned Nelson the right to remain a starter after Arizona returned to full health in the rotation, knocking Montgomery to the bullpen.

But Pfaadt is also a young and evolving pitcher who was the Diamondbacks’ workhorse last season, leading the team with 181.2 innings. His ERA ballooned to 4.71 after some struggles in the second half, but he was effective for most of the year and his 3.61 FIP (fielding-independent pitching) suggests his final numbers should have been better.

There are no obvious answers regarding the fifth starter, but having depth — last year painfully illustrated — is necessary with the number of pitching injuries teams absorb these days. In a National League as deep as the current iteration, rostering a fifth starter with Pfaadt’s or Nelson’s abilities is a separating factor.

Rodriguez, meanwhile, will be counted on to give them more than last year, which was derailed by a shoulder injury in spring training that limited him to 10 games.

Rodriguez makes $20 million annually, turns 32 years old next year and is one season removed from a 3.30 ERA and 3.66 FIP in 2023 with Detroit.

Gallen and Kelly — along with Montgomery — are entering the final seasons of their respective contracts.

Gallen, a Scott Boras client, will enter the market at 30 years old and has the opportunity to showcase himself for a massive payday after a solid but inconsistent 2024 (3.65 ERA) compared to his superb previous two seasons. Kelly will compete to bounce back in his age-36 season after a shoulder injury plagued him for much of last year.

Signing Burnes to a multi-year deal keeps an ace-caliber arm atop the rotation beyond 2025 no matter what happens. Rodriguez, Pfaadt and Nelson are all under control beyond 2026, while the D-backs have well-regarded pitching prospects in the upper minors who will compete for opportunities in the coming years (Diaz, Mena and Yu-Min Lin, for example).

The Diamondbacks’ pitching staff assembled a poor output in 2024 as it dealt with injuries and performance woes that pushed players into different roles. Not only did they finish 27th in ERA at 4.62, but Arizona ranked bottom five in WHIP, strikeout rate and hard hit percentage.

Run prevention has been a publicly expressed goal of the front office going into next season, which it addressed with new pitching coach Brian Kaplan and now an ace joining the staff.

If the D-backs can get better injury fortune — or manage when players go down more effectively — they can run out the horses to push up to 175-200 innings. That would make life much easier for manager Torey Lovullo and a bullpen that put a lot of miles on its best weapons by the end of last year.

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