MLB Insider Suggests Arizona Diamondbacks Could Trade Zac Gallen, Merrill Kelly

As the Arizona Diamondbacks wait for updates on Corbin Burnes' injury, Ken Rosenthal believes the front office could become sellers and look to move Zac Gallen or Merrill Kelly.

Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen reacts against the Pittsburgh Pirates at Chase Field. | Mark J. Rebilas-Imagn Images

The Arizona Diamondbacks' season could be hanging by a thread.

Corbin Burnes, who inked a $210 million contract with the D-backs in December, left his last start Sunday with right elbow inflammation. The team has yet to come forward with a more specific diagnosis or timetable for the ace's return, but they could be preparing for the worst possible outcome.

During FOX Sports' MLB coverage Monday night, insider Ken Rosenthal joined the broadcast to tackle a handful of headlines from across the league. He started off by addressing Burnes' injury, and what it could mean to a 28-31 Arizona squad moving forward.

"If Burnes is out, they're likely looking at – I think – becoming a seller," Rosenthal said. "And who to they have to sell? Well Zac Gallen is a potential free agent, Merrill Kelly the same."

Rosenthal also mentioned first baseman Josh Naylor as another pending free agent who could get moved if Diamondbacks owner Ken Kendrick is looking to hack away at a franchise-record $181 million payroll.

Let’s check in with @Ken_Rosenthal for some updates around the league:
▫️ Who could the Dbacks trade if they become sellers this season?
▫️ The Royals calling up Jack Caglianone
▫️ When could Mookie Betts return to the Dodgers lineup? pic.twitter.com/5IsNVJLGJ2

— FOX Sports: MLB (@MLBONFOX) June 3, 2025

Burnes is 3-2 with a 2.66 ERA, 1.166 WHIP and 2.1 WAR through 11 starts this season, making the four-time All-Star and former Cy Young winner the Diamondbacks' most productive starter in 2025.

Kelly has also been enjoying a solid campaign thus far, going 5-2 with a 3.78 ERA, 1.058 WHIP and 1.3 WAR through 12 starts. That 36-year-old righty carries a $7 million salary this season.

As for Gallen, who placed top-five in NL Cy Young voting in 2022 and 2023, he has come out of the gates ice cold. Through 12 appearances, the $13.5 million right-hander is 3-7 with a 5.54 ERA, 1.395 WHIP and 0.3 WAR.

Still, plenty of teams would presumably covet the 29-year-old former All-Star on the trade market.

Arizona doesn't have the high-level one-through-five rotation to survive multiple losses due to either injury or trade, so any major move would effectively signal the front office punting on the season. Brandon Pfaadt has an ERA over 5.00, Eduardo Rodriguez has an ERA over 7.00 and Jordan Montgomery is out for the year after undergoing Tommy John surgery this spring.

Less than two months remain until the trade deadline, but the sooner the Diamondbacks look to trade a starting pitcher, the more they could get back in return.

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