What Corbin Burnes Brings to the Diamondbacks in 2025

Breaking down the projections, proficiencies and concerns surrounding Arizona's newest ace.

Aug 10, 2024; St. Petersburg, Florida, USA; Baltimore Orioles starting pitcher Corbin Burnes (39) throws a pitch in the first inning against the Tampa Bay Rays at Tropicana Field. Mandatory Credit: Jonathan Dyer-Imagn Images / Jonathan Dyer-Imagn Images

The Arizona Diamondbacks shocked the baseball world late Friday night, signing right-handed ace Corbin Burnes to a franchise record $210 million deal over six years.

Burnes immediately becomes Arizona's top arm, and his years of success well-warrant a large contract.

So what exactly can the Diamondbacks expect out of Burnes in the 2025 season? There are two primary projections available as of now, coming from ZiPS and Steamer.

Steamer projects a perhaps surprisingly high ERA of 3.71 for Burnes, while ZiPS expects a 3.28.

But for the purpose of this article, we'll take the average of the two projections. While these systems tend to look for regression to the mean for most players, regardless of their reputation, even Burnes' relatively low projections look like very solid seasons in the D-backs' rotation.

Burnes' Projections

Averaged out, ZiPS and Steamer expect Burnes to pitch just under 186 innings in 2025. That number is immediately higher than any total that a member of the 2024 rotation reached the prior season.

As for Burnes' ERA, the projection expects it to hover close to 3.50, also a better figure than any of 2024's starters saw. He's expected to put forward a 3.42 FIP to back it up, along with a 121 ERA+, 21% above league average.

His K/9 is set to hover just below 9.00, lower than he's been known to do, but an improvement over the 8.38 it was in 2024. He's still expected to limit walks to around a 2.5 BB/9 and mitigate home runs to a 0.91 HR/9 projection.

In total, projections expect the right-hander to be worth an average of 3.7 fWAR, generally in line with his previous few seasons' outputs. Remember, these projections are not gospel, and weigh recent seasons more heavily than others.

Burnes is likely a better overall pitcher than these numbers might suggest.

Why Burnes might outperform projections

Even if Burnes stays around what his averaged projections show, he'd be stepping in as the top arm in a struggling D-backs rotation.

But the ace's results over the past few seasons make it hard to assume he's about to have a more pedestrian 2025, even with some regression from his excellent 2024 season.

Burnes pitched to a 2.92 ERA in 2024, and has a 2.88 ERA and 3.01 FIP since 2020, when he began starting in a more full-time capacity. Since then, he's been one of MLB's best, winning the NL Cy Young Award with the Brewers in 2021, and putting up consistently great results.

His stuff is top-tier, and his velocity hasn't seen a dip as he's aged. His command has remained elite, and he was worth a +27 Pitching Run Value in 2024, a 98th percentile number.

Even his xERA sat at an impressive 3.34 number, and despite a strikeout rate seeing a dip, still managed to induce whiffs and chases at a high rate, while still maintaining a top-20% ground ball rate and being among the best at limiting hard contact.

This proficiency comes from his raw stuff, his command, and the diversity of his arsenal. Burnes has a deep six-pitch arsenal, but relies heavily on a cutter that's been (for the most part) among the league's best pitches, and a whiff-inducing curve.

He also throws a slider, changeup, sinker and sweeper, though these four made up just 34% of his pitch usage in 2024. He's able to hit 97 MPH on his sinker, but even the cutter immediately marks the the highest average velocity of any D-backs' starter at 95.3 MPH.

The Concern

The main concern with Burnes, entering his age-30 season, comes from a declining strikeout rate. While he's been known to rack up whiffs and punchouts throughout his career, he saw a career-low 8.38 K/9 in 2024, good for only a 23.1% K rate.

Considering his K% sat in the 30s from 2020-2022, and the K/9 cleared 10.00 from 2019-22, that number does provide a modicum of concern for Burnes going into 2025.

This dip is a near direct result of a decline in said cutter. One of MLB's top pitches during the 2020s, the pitch saw a major dip in whiff rate last season, averaging a mere 19%.

However, according to an article from CBS Sports' Chris Towers, Burnes diagnosed his own issue, noting that the cutter's elite movement began to resemble that of a "[poor] four-seam fastball."

With that said, Burnes went back into the lab, and came out with a much-improved cutter. After beginning the season with just a 17.6% whiff rate on the pitch, he saw a resurgence in it from September into the Postseason, increasing it to a more impressive 22.9%.

However, that 22.9% is still merely in line with 2023, where it was down from 27.8% and 33.5% in 2022 and 2021. Granted, these adjustments can take time to fully take hold, and it's very possible Burnes gets his cutter closer to 2021/2022 form in due time, but it is something to watch out for.

Burnes also struggles heavily to hold runners on. For his career, he's allowed 92 steals, with only 16 Caught Stealing in that time.

That came to a head in 2024, where he allowed an astounding 41 steals, nearly half his career total, against just six caught stealing.

This might not be the biggest aspect of a pitcher's game, but could have an impact on his overall run prevention.

The D-backs do have a young catcher that excels at throwing out base-stealers in Gabriel Moreno, however, so it might be wise to prevent Burnes from pitching to Adrian Del Castillo or Jose Herrera in 2025 when possible.

Conclusion

Don't let some of the poorer numbers fool you - Burnes is still a top-tier ace in MLB, and was debatably the best starting pitcher on the free agent market.

The Diamondbacks will be adding a Cy Young winner with a history of success and excellent results. While he is 30 years old, he's only been a full-time starter since 2021, and he's been an elite one.

He performs in high-pressure enviroments as well. In nine career postseason appearances (but only three starts), he's posted a cumulative 2.33 ERA. In 2024, he went eight brilliant innings of one-run ball in his lone playoff start--and was stuck with the loss.

In fact, his only poor outing came in 2023, where he allowed four runs in four innings of the NL Wild Card to the D-backs, the very team he's set to join.

But even if his numbers tail off toward his 2023/2024 form, and he hovers around his projections, Burnes is still set to put forward a very solid season.

As of now, there's little true doubt that he'll be able to lead Arizona's rotation in 2025, especially if his cutter does continue an upward trajectory back to full form.

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