The Arizona Diamondbacks may not have solved their bullpen overnight, but according to reporting from Nick Piecoro, the most important reinforcement could arrive sooner than expected—and it didn’t come via free agency. Left-hander A.J. Puk is trending toward an earlier return in the opening months of the 2026 season, a development that could quietly reshape Arizona’s relief outlook.
Arizona’s bullpen was one of the defining weaknesses of last season. Injuries piled up quickly, and the absences of Puk and Justin Martinez left the Diamondbacks scrambling for leverage arms they simply did not have. General manager Mike Hazen acknowledged as much while discussing the club’s recent signing of Taylor Clarke, noting that while more work remains, internal reinforcements are expected as the season progresses.
That comment was not throwaway optimism. It was a clear nod toward Puk’s recovery timeline.
Why A.J. Puk Changes the Bullpen Math
When healthy, Puk has been far more than just another lefty. Over his two seasons in Arizona, he posted a 1.78 ERA across 35.1 innings, holding hitters to a microscopic .155 batting average. His WHIP sat at an elite 0.849, and his strikeout rate jumped to nearly 14 per nine innings—numbers that place him firmly in late-inning territory.
In 2024, Puk looked dominant before the elbow issue shut him down. Opponents managed just a .204 on-base percentage and a .278 slugging percentage against him, translating to a .482 OPS. His expected outcomes supported it as well. Statcast indicators showed strong chase rates, above-average whiff numbers, and consistent command within the strike zone.
Even during his abbreviated 2025 appearance, even though he was clearly not at full strength, the underlying traits remained visible. The raw ERA and surface stats suffered in just eight innings, but the velocity held, and the spin profile suggested the arm itself was trending in the right direction before the shutdown.
Timing Matters More Than Spending
The Diamondbacks’ offseason additions—Clarke, Michael Soroka, and Merrill Kelly—reflect a front office operating within realistic constraints. Hazen openly admitted that landing a proven eighth- or ninth-inning arm was unlikely. That reality makes Puk’s return feel less like a bonus and more like a necessity.
If Puk returns within the season’s first couple of months, as Piecoro reports is possible, Arizona suddenly gains a controllable, high-leverage lefty without sacrificing prospects or payroll flexibility. That allows Hazen to deploy matchups more aggressively and avoid overexposing unproven arms early in the year.
It also stabilizes roles. Instead of forcing younger relievers into leverage spots, the Diamondbacks can let Puk absorb the toughest left-handed pockets while Martinez works his way back later in the season.
Bullpen fixes rarely arrive with headlines in January. They come in April, May, and June—often from within. That is exactly how this one is shaping up.
Arizona doesn’t need Puk to be a savior. They need him to be what he has already shown he can be: a dominant, strike-throwing left-hander who shortens games and changes how opponents build lineups late.
If his return does come sooner than expected, the Diamondbacks’ bullpen won’t just improve. It may finally begin to resemble the unit the front office envisioned all along—one built less on splashy signings and more on getting its best arms back when they matter most.
Diamondbacks Could Get Major Bullpen Boost Sooner Than Expected