Merrill Kelly Returns to Arizona: D-backs’ Rotation Upgraded

The D-backs bring back Merrill Kelly on a two-year, $40M deal. We break down how his return impacts Arizona’s rotation and long-term pitching outlook.

The Diamondbacks made their rotation splash of the offseason, bringing back Merrill Kelly on a two-year, $40 million deal. Kelly returns home to Arizona less than five months after the team dealt him for three pitching prospects at the trade deadline.

This certainly comes as a pleasant surprise, as previous signals from manager Torey Lovullo suggested both Gallen and Kelly weren’t coming back. At best, they were going to retain one of the two pitchers, with the latter being much more likely. There is sentimental value in bringing back a fan-favorite, given his baseball roots in the state of Arizona.

Kelly’s market was more or less set by the two-year, $46 million extension Seth Lugo signed with the Royals. That piece was published three days before the trade, correctly predicting how much it would take to bring him back to Arizona.

It made sense that Arizona paid a premium to bring back the 37-year-old Kelly. The number of starters who can provide 30 starts, 180 innings, and a sub-4.00 ERA continues to shrink. The few who can, which includes both Gallen and Kelly, get paid handsomely. That’s why it took $20 million per year to bring him back.

At the price of $11 million per WAR, the breakeven point for Kelly is 2.0 WAR per season. It’s a deal that should age well for the D-backs, even with Merrill entering his Age-37 season in 2026.

D-backs Rotation Situation After Merrill Kelly Signing

In addition to Merrill Kelly, the D-backs signed the oft-injured Michael Soroka to a one-year deal. With both pitchers in the fold, this is what Arizona’s projected rotation looks like.

1. RHP Merrill Kelly (32 GS, 3.52 ERA, 184 IP)

2. RHP Ryne Nelson (33 G/23 GS, 3.39 ERA, 154 IP)

3. LHP Eduardo Rodríguez (29 GS, 5.02 ERA, 154.1 IP)

4. RHP Brandon Pfaadt (33 GS, 5.25 ERA, 176.2 IP)

5. RHP Michael Soroka (22 G/17 GS, 4.52 ERA, 89.2 IP)

It’s a rotation group that carries significant injury risk, placing a premium on rotation depth. Kelly is 37, Rodríguez will be 33 in April, and Soroka is coming off the healthiest season of his career since 2019. While it can be reasonable to project 150+ innings for Kelly, Pfaadt, and Nelson, the rotation is going to have to cover 900 innings over the season. That’s going to place a lot of stress on the organization’s depth options.

Arizona has some MLB-ready options in Cristian Mena, Kohl Drake, Mitch Bratt, and Dylan Ray on their 40-man roster, but the quartet combine for one career start. The needs of the roster may decide what their depth options are. Mena is a candidate to start the season on the major league roster as a long reliever, to get innings out of him until a rotation spot opens up or they convert him to short relief.

The organization has three potential starter options rehabbing from Tommy John surgery. Blake Walston and Corbin Burnes are expected to return during the season, but the question is whether the rotation can hold up long enough and if Burnes can hit the ground running. If the answer to both questions is yes, the D-backs could make some noise in the 2026 postseason picture.

Longer-Term View of the D-backs Rotation Options

The deal ensures that Kelly, Nelson, Rodríguez, and Pfaadt are under contract through at least the 2027 season. Burnes will likely opt into the final four years of his deal, valued at $140 million, with two seasons affected by elbow surgery. Taking those into account, this is the control situation for Arizona’s top five starters.

• RHP Merrill Kelly: 2027

• Eduardo Rodríguez: 2027 (2028 vesting option)

• RHP Ryne Nelson: 2028

• RHP Brandon Pfaadt: 2030 (2031 club option)

• Corbin Burnes: 2030