Diamondbacks To Sign Merrill Kelly

The Diamondbacks are finalizing a contract with right-hander Merrill Kelly, according to a report from Ken Rosenthal of The Athletic. Rosenthal adds that it’s a two-year, $40MM pact. Jon Heyman of The New York Post adds that the deal is pending a physical. Arizona has a full 40-man roster, so a corresponding move will be necessary before Kelly’s deal can become official.

Kelly, 37, returns to the team with which he has spent nearly his entire major league career. Though initially drafted by the Rays in the eighth-round of the 2010 draft, Kelly made his big league debut with the Diamondbacks back in 2019 after a four-season stay in Korea as a member of the KBO’s SK Wyverns (now known as the SSG Landers). After a pedestrian rookie campaign in the majors where he pitched to a league-average ERA in 32 starts, Kelly managed to fashion a role for himself as one of the better mid-rotation arms in the majors.

Since the start of the 2022 campaign, Kelly has pitched to a 3.47 ERA (120 ERA+) in 108 starts. He’s struck out 23.1% of his opponents while walking 7.7% in that time, leaving him with a 3.81 FIP. While Kelly’s peripherals (including a 4.03 SIERA) cast him as a step down from your prototypical front-end starter, the veteran has managed to remain a quality rotation piece eating innings at a high level (with at least 175 innings of work in three of the last four seasons) and endeared himself to fans in Arizona when he delivered a brilliant 2.25 ERA during the club’s run to the World Series in 2023.

Amid a disappointing 2025 season where the Diamondbacks were ravaged by injuries to everyone from star closers Justin Martinez and A.J. Puk to newly-signed ace Corbin Burnes, the team engaged in a sell-off at this year’s trade deadline and shipped Kelly to the Rangers in exchange for a trio of pitching prospects. Kelly put up uninspiring numbers across ten starts with the Rangers, posting a 4.23 ERA and near-matching 4.18 FIP across 55 1/3 innings of work. Even while the veteran was in Texas, an offseason reunion with the Diamondbacks was already being speculated upon. “Definite” interest in a reunion with Kelly was reported on Arizona’s side shortly before last week’s Winter Meetings, and now the sides have come together on a deal.

Turning to the deal itself, Kelly’s $40MM guarantee clocks in just ahead of the two years and $36MM MLBTR predicted for the right-hander when ranking him as the #25 free agent in this offseason’s Top 50 MLB Free Agents list. Perhaps that slight premium the Diamondbacks paid for Kelly’s services was the cost of jumping the market; while the free agent market for position players and especially relievers has kicked into gear in a big way already, Kelly is just the third starting pitcher from MLBTR’s Top 50 to sign a contract this offseason. He joins Dylan Cease and Cody Ponce, both of whom received guarantees that slightly eclipsed MLBTR’s prediction.

Now that he’s set to return to Arizona, Kelly stands as the favorite to start for the Diamondbacks on Opening Day this year. He’ll join a rotation that already added Michael Soroka earlier this offseason while reuniting with former teammates Eduardo Rodriguez, Brandon Pfaadt, and Ryne Nelson. Burnes could be a factor later in the season but is not expected to pitch until sometime in the second half of the season. While the team’s rotation certainly looks much more complete with Kelly back in the fold, bringing the right-hander back into the fold shouldn’t stop the team from pursuing other rotation additions after the club’s pitching staff finished 19th in the majors with a 4.29 ERA last year.

Of course, adding beyond this could prove to be easier said than done. The Diamondbacks are projected for a payroll just north of $171MM in 2026, according to RosterResource. That rises to north of $205MM for luxury tax purposes. GM Mike Hazen has suggested that, while Arizona’s payroll would likely be moving downward from its 2025 level, that would still leave the team with room to spend. The club spent $188MM on its payroll last season, however, meaning they currently sit less than $17MM from that mark.

Perhaps that leaves enough wiggle room to reunite with Paul Goldschmidt on an affordable one-year deal, a move the Diamondbacks have been said to be contemplating, but Kelly will surely go down as the team’s biggest expenditure unless an increase in payroll is approved or the team makes a trade that clears salary. To that latter point, the hot stove has been burning with Ketel Marte trade buzz in recent weeks. Moving Marte would certainly clear payroll off the books, though Hazen has consistently downplayed the likelihood of a deal surrounding Marte actually coming together.