D-backs Have Made Notable Effort to Improve This Area

Arizona's offseason approach has notably emphasized this weakness.

Sep 15, 2025; St. Louis, Missouri, USA; St. Louis Cardinals third baseman Nolan Arenado (28) fields a ground ball hit by Cincinnati Reds third baseman Santiago Espinal (not pictured) in the ninth inning at Busch Stadium. Mandatory Credit: Joe Puetz-Imagn Images | Joe Puetz-Imagn Images

The Arizona Diamondbacks have made a pair of notable position-player additions this offseason: signing first baseman Carlos Santana and trading for platinum glove third baseman Nolan Arenado.

To some, these moves might seem a bit strange, or out of the realm of what Arizona truly needed this offseason — pitching.

But while the D-backs have made some pitching moves, as well (such as Merrill Kelly, Michael Soroka and a handful of low-risk bullpen signings), where they will most likely truly improve is in the quality of their infield defense.

Arizona Diamondbacks Making Effort to Improve Infield Defense

Aug 19, 2025; Phoenix, Arizona, USA; Cleveland Guardians first baseman Carlos Santana against the Arizona Diamondbacks at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | Mark J. Rebilas-Imagn Images

GM Mike Hazen did not try to hide this intent. In fact, he cited the D-backs' poor first-half defense as one of the biggest disappointments from 2025 in his end-of-season press conference.

"I do think on the whole our defense was considerably different in the second half. I do think that helped smooth out the pitching that we were all very frustrated by in the first half of the season," Hazen said at the time.

"I think that's probably something that I'm going to look to lean into a little bit more aggressively into the offseason. I think ensuring that our defense at all eight positions is where we need it to be."

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And, at least on paper, they certainly have done so. Arenado is one of the best third base defenders in MLB history, with six Platinum Glove Awards to his name.

"We think he really solidifies our defense on the infield. It's been a priority for us to improve our defense, which I believe is going to have a direct impact on our pitching in a significant way," Hazen said of Arenado's acquisition.

Santana, meanwhile, was worth +12 Defensive Runs Saved at first base in 2025, and has been a consistent plus defender regardless of the effectiveness of his bat.

To an extent, those errors did contribute a good portion of Arizona's pitching woes. The D-backs made the fewest errors in all of MLB in both 2023 and 2024. They committed a collective 22 more in 2025 (84) than they did the year prior (62).

That defense had been an identity for Arizona. It helped the team stay in close games and even win some in their exceptional 2023 and 2024 seasons. The step back was significant, on par with the overall theme of disappointment and underperformance in 2025.

With two premier defenders manning the corner infield positions, Arizona should be in position to get back to their sharp ways in 2026.

"Improving our defense was a significant focus for us this offseason, and it continues to be so," Hazen said. "I want to have a good defensive team all over the field next year."