Merrill Kelly Shelling by Nationals Latest Concern for D-backs

Suddenly the Diamondbacks rotation has multiple large question marks

Jun 5, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Merrill Kelly (29) throws against against the Washington Nationals during the first inning at Chase Field. Mandatory Credit: Arianna Grainey-Imagn Images | Arianna Grainey-Imagn Images

The Arizona Diamondbacks went into the 2025-26 offseason looking to rebuild their rotation. With ace Corbin Burnes having had Tommy John Surgery and two mainstays in Merrill Kelly and Zac Gallen becoming free agents, there were over 90 starts to fill.

Mike Hazen's front office decided to run it back with Kelly and Gallen, signing both for the 2026 season. Kelly was signed to a two-year, $40 million deal, and Gallen to a one-year, $22 million deal (worth $18 million after deferrals).

To say it hasn't worked out would be a massive understatement. Burnes, signed to a six-year, $210 million contract, had a setback in his recovery from Tommy John Surgery. He was diagnosed with a Teres Major strain this past week, and won't return before September, if at all.

Gallen was smacked around by the Dodgers on Wednesday for nine runs on five hits, resulting in seven runs. That ran his season ERA up to 5.32, on the heels of a 4.83 ERA last year. Any hopes of a revival based on a run of good starts late in 2025 have evaporated.

Merrill Kelly Adds to the D-backs Rotation Concerns

Jun 5, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Merrill Kelly (29) throws against against the Washington Nationals during the first inning at Chase Field. Mandatory Credit: Arianna Grainey-Imagn Images | Arianna Grainey-Imagn Images

On Friday night Kelly was pummeled by the Washington Nationals for seven runs in five innings. That included three homers and three walks allowed. The veteran right-hander never looked right from the moment the game started.

His outing began several minutes late as Kelly disappeared into the dugout just before game time for undisclosed reasons, delaying the 6:40 start to 6:44. When he came out to finally start the game he walked James Wood and gave up two-run homer to Luis Garcia Jr., spotting the Nationals a quick 2-0 lead.

Wood led off the third inning with a homer, but that was just the start, as nine men came to the plate and three more runs scored. Finally, one more solo homer in the fifth by Daylen Lile punctuated the ineffectiveness for Kelly.

The D-backs went on to lose the game 14-1, as the Nationals scored seven more runs against the bullpen. The loss dropped their record to 33-30, pushing them a half game back of the Pirates for the third NL Wild Card spot.

The outing ran Kelly's season ERA to 5.71 in 10 starts, 58.1 innings. His FIP, or Fielding Independent Pitching, number is 6.12. That is because he's given up a whopping 13 homers, walked 25, and struck out just 37.

Kelly's season started off with a back injury, due to an intercostal nerve issue. Rushed back through his rehab process, he was horrendous over his first four outings, giving up 21 runs in 19 innings for a 9.95 ERA.

Kelly appeared to be righting his ship over the next five outings, at least on the surface. He went 4-0 with a no-decision In 34.1 innings, posting a 2.36 ERA. That was accompanied by a 4.21 FIP, however, including four more homers and just 19 strikeouts. Batted balls were finding gloves and the overall results were good but that good fortune ran out Friday.

Kelly Struggling vs Left-hand Batters

Arizona Diamondbacks pitcher Corbin Burnes (back) and pitching coach Brian Kaplan watch pitcher Merrill Kelly (29) throw during spring training workouts on Feb. 10, 2026, at Salt River Fields in Scottsdale. | Rob Schumacher/The Republic / USA TODAY NETWORK via Imagn Images

A new issue has emerged. Kelly is struggling mightily versus left-hand batters. He came into the game with a .271 batting average and .926 OPS against lefties, including seven homers.

The Nationals saw this and stacked six lefties in a row plus two switch hitters against Kelly. He came out of the game with a .279 B.A. and a .982 OPS against lefties.

Against right-hand batters Kelly has been more or less the same as his career average. The .258 BA and .705 OPS are not that much worse than his career .236 BA and .694 OPS against right-hand batters.

This is a similar problem to what Brandon Pfaadt is experiencing. Kelly is simply not locating his four-seam fastball well up and in to move hitters off the plate, and his cutter has been getting hammered repeatedly. Last year the cutter was very effective versus lefties, just like Pfaadt.

Whether there is a quick fix, or this is just a 37-year-old pitcher entering decline remains to be seen. Pitching coach Brian Kaplan has his work cut out for him to help Kelly, Gallen and Pfaadt figure it out.

The bottom line for the Diamondbacks however is they're paying $95 million for two under performing and one injured and unavailable starter.

Michael Soroka, Eduardo Rodriguez, and Ryne Nelson are holding it together in the rotation for now. Pfaadt, meanwhile, was optioned to Triple-A, and there is little if any promising starting pitching depth among the prospects in the Reno rotation ready to contribute.

These are the challenges Arizona faces as they try to stay in the playoff hunt prior to the August 3 trade deadline.