6 Most Shocking Developments From Diamondbacks' 2026 Season

Arizona's biggest (positive) surprises.

Sep 27, 2026; San Diego, California, USA; Arizona Diamondbacks pitcher Brandyn Garcia (55) during the sixth inning against the San Diego Padres at Petco Park. Mandatory Credit: Denis Poroy-Imagn Images | IMAGN IMAGES via Reuters Connect

The Arizona Diamondbacks' 2026 may have ended in disappointment, but it certainly was not devoid of the unexpected joys that accompany a 162-game marathon regular season.

Despite the Diamondbacks ultimately spending this postseason at home for the third straight year, there is plenty to reflect on in a positive light this offseason.

As any 162-game followers know, you cannot predict baseball. And that is part of MLB's allure. Here are five of the Diamondbacks' most unexpected — positive — developments during their 86-76 regular season:

1: Diamondbacks bullpen becomes weapon

Sep 27, 2026; San Diego, California, USA; Arizona Diamondbacks pitcher Juan Morillo (62) delivers during the fifth inning against the Arizona Diamondbacks at Petco Park. Mandatory Credit: Denis Poroy-Imagn Images | IMAGN IMAGES via Reuters Connect

All fans likely wanted to see out of Arizona's bullpen was an improvement from 2024 and 2025, in which they finished bottom-five in reliever ERA. That lack of bullpen talent led to many a frustrating blown lead.

But in 2026, Arizona made some small additions — and saw some massive jumps from certain relievers. They signed Taylor Clarke (2.96 ERA) and Jonathan Loaisiga (2.42 ERA) and saw big year-two leaps from Juan Morillo (2.24 ERA) and Brandyn Garcia (1.93 ERA).

In total the D-backs moved up to 16th in baseball with a 4.07 bullpen ERA. But by Win Probability Added (+8.24), Arizona had the fourth-most-impactful relief corps in baseball.

Suddenly, the D-backs' bullpen went from a massive weakness to a serious weapon.

2: Eduardo Rodriguez becomes Diamondbacks' ace

Sep 6, 2026; Houston, Texas, USA; Arizona Diamondbacks starting pitcher Eduardo Rodriguez (57) warms up. before the game against the Houston Astros at Daikin Park. Mandatory Credit: Troy Taormina-Imagn Images | IMAGN IMAGES via Reuters Connect

Eduardo Rodriguez had back-to-back terrible seasons to start his D-backs career, posting ERAs above 5.00 and spending plenty of time on the IL in both 2024 and 2025.

But Rodriguez came into spring training in better physical shape. His stuff and command immediately appeared vastly better.

Arizona's veteran lefty was able to post a 2.89 ERA and win 16 games this season; he provided exactly the front-end veteran pitchability the Diamondbacks needed with a relatively unstable rotation.

Perhaps some of it was necessary positive regression. But there's simply no denying how impactful Rodriguez was to a team that outperformed pre-season expectations.

3: Michael Soroka's excellence

Sep 27, 2026; San Diego, California, USA; Arizona Diamondbacks pitcher Michael Soroka (34) delivers during the first inning against the Arizona Diamondbacks at Petco Park. Mandatory Credit: Denis Poroy-Imagn Images | IMAGN IMAGES via Reuters Connect

If right-hander Michael Soroka had been healthy all season, he might have managed to challenge Rodriguez for the ace title.

Arizona signed Soroka to a one-year, $7.5 million deal this offseason, and he looked much more like the version of himself that was an All-Star for the Braves in 2019.

Soroka posted a 3.41 ERA and nine wins despite being limited to 116 innings, which was still his heaviest workload since that 2019 campaign.

Soroka was exceptional value for the Diamondbacks this year, and said he would "absolutely love to return" to Arizona in 2027 and "take care of some unfinished business."

4: Gabriel Moreno's breakout

Sep 24, 2026; Denver, Colorado, USA; Arizona Diamondbacks designated hitter Gabriel Moreno (14) hits a three-run home run in the first inning against the Colorado Rockies at Coors Field. Mandatory Credit: Ron Chenoy-Imagn Images | IMAGN IMAGES via Reuters Connect

Gabriel Moreno is a talented player when he's on the field, and many expected a productive season. But what Moreno did in 2026 was more than just a career season.

Moreno slashed .311/.388/.486 for a .874 OPS — all career highs for a full season. The .311 average was enough for him to claim Arizona's first ever National League batting title.

He hit a career-high 33 doubles, 16 home runs and brough in 83 RBI, all while playing Gold Glove defense and appearing in 130 games.

5: Nolan Arenado's bounce-back season

Sep 25, 2026; San Diego, California, USA; Arizona Diamondbacks third baseman Nolan Arenado (28) hits a two-run home run during the third inning against the San Diego Padres at Petco Park. Mandatory Credit: Denis Poroy-Imagn Images | IMAGN IMAGES via Reuters Connect

The Diamondbacks traded a low-level pitching prospect for Nolan Arenado ahead of 2026, with the St. Louis Cardinals picking up much of the tab on the former superstar.

Though he did not hit well through the first several weeks of the season, Arenado eventually found a rhythm and began to produce at a much higher clip than his past two years.

The future Hall of Fame third baseman played strong defense, but the real surprise was his .255/.331/.475 slash and .806 OPS — his best numbers since 2022.

Arenado hit 30 homers, which more than doubled his 2024 and 2025 combined output and led the Diamondbacks. He was named the NL Player of the Week for an OPS over 1.400 in the final week of the regular season.

Arenado might not be the superstar he once was, but he was a very valuable player for Arizona, for just $5 million. He's under contract for 2027, as well.

6: Brandon Pfaadt's post-option resurgence

Sep 25, 2026; San Diego, California, USA; Arizona Diamondbacks pitcher Brandon Pfaadt (32) delivers during the first inning against the Arizona Diamondbacks at Petco Park. Mandatory Credit: Denis Poroy-Imagn Images | IMAGN IMAGES via Reuters Connect

Brandon Pfaadt struggled to a 4.71 ERA in 2024. He threw to a 5.25 ERA in 2025. After two brutal months of 2026 and a demotion to the bullpen, his ERA sat at 5.92.

And then, the Diamondbacks sent him to Triple-A Reno for a brief tune-up. Pfaadt returned to the starting rotation with some minor tweaks and dominated for nearly the rest of the season. He pitched to a 1.88 ERA in July and a 2.54 ERA in August.

His full-season ERA lowered from 5.92 to 3.77 — a career best. His expected ERA (3.90) and FIP (3.89) suggested his positive outcomes were deserved.