D-backs Desperately Need Improvement in These Areas for 2026

The Arizona Diamondbacks were undeniably a flawed baseball club in the 2025 season. Despite coming into the year with sky-high expectations, Arizona missed out on a playoff berth.

It's relatively obvious which areas of the team truly let them down in 2025. Those needs are not secrets, and have been acknowledged by both GM Mike Hazen and manager Torey Lovullo.

Below are the three most crucial areas that are in dire need of a major improvement in the 2026 season, regardless of personnel and roster depth.

1: Diamondbacks Bullpen

The most obvious issue plaguing the D-backs in 2025 was undeniably the poor performance of their relief pitchers. Granted, part of that can be attributed to suffering multiple season-ending injuries to key arms like A.J. Puk, Justin Martinez and later Shelby Miller.

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The Diamondbacks posted a 4.82 relief ERA over the course of the season. That was good for the fourth-worst figure in all of baseball. They faced the fifth-most save opportunities in baseball (71), but only managed to convert a staggering 42 of those saves — a dismal 59% save rate.

The D-backs had no true closer, and that once again hurt the rest of their battered, journeyman-filled bullpen.

"We need to do a better job of putting together a bullpen," Hazen said. "I think Torey [Lovullo] and I have talked about this. How we're using some of the bullpen, we need to do a better job at.

"Injury as it happens in the bullpen, nobody in baseball has figured out how to put their finger on it necessarily. But it's not luck. We can be doing a better job. We are going to spend some time this offseason really diving into those types of things."

2: Diamondbacks' Defense

The Diamondbacks have been known as a defensive club. In fact, they've been near the top of that class most seasons under Torey Lovullo, even when struggling as a whole.

And yet, that normally-sound defense was uncharacteristically poor in the 2025 season.

Back in 2023, the D-backs made the fewest errors in baseball (56). In 2024, they retained their MLB-leading fielding, making 62 errors — also the fewest.

In 2025, that total spiked to 84, dead center of MLB at 15th. Their fielding percentage was a slightly-below-average .986.

Part of that could be attributed to the departure of Christian Walker at first base. Josh Naylor and Eugenio Suárez made their fair share of errors prior to their respective trades, and Geraldo Perdomo made a career-high 18 errors at shortstop, despite putting up a seven-WAR season.

Arizona needs a return to their previous identity if they want to help out a struggling pitching staff.

3: Diamondbacks' Rotation

Arizona's starting pitchers provide the most uncertainty at this stage of the offseason. With the departure of Merrill Kelly and the expected departure of Zac Gallen in free agency, the D-backs will be down to just Ryne Nelson, Eduardo Rodriguez and Brandon Pfaadt as sure-fire rotation members.

In 2025, that group struggled as a whole, even with Gallen and Kelly. Arizona got a 4.29 ERA (11th-worst in MLB) from their rotation, and that includes a second-half surge from Gallen, the consistent excellence of Nelson and a hot streak from Rodriguez.

The D-backs need to add personnel, no doubt, but they also need better performances out of their in-house arms.

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"The starting pitching is going to be something we're going to need to focus in on going into the offseason for sure," Hazen said.

"That's probably the number one area outside of building the bullpen again that we're going to have to focus in on."

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