Diamondbacks Admit Lineup Weakness; Bullpen Surgery Looms Before Deadline

Mike Hazen didn't mince words on MLB Network Radio today: the Diamondbacks are hunting for upgrades on both sides of the ball before the July trade deadline. The GM acknowledged a glaring offensive void—his team ranks bottom-three in batting average, on-base percentage, and slugging against right-handers, with an 85 wRC+ (worst in baseball)—and confirmed the need for at least one left-handed bat to inject power into a lineup that's functionally underwater against same-side pitching.

But the bullpen conversation reveals something more important about Arizona's roster construction than the headline suggests. Yes, Hazen stated the obvious—"everybody needs bullpen"—and on the surface, the numbers look manageable. His relievers have thrown just 209 1/3 innings through 64 games (second-fewest in MLB), posting a 4.13 ERA masked by a strong 3.84 SIERA. However, peel back the aggregate and the picture sharpens. Brandon Pfaadt and Andrew Hoffman have been demoted to Triple-A Reno. The remaining core—Sewald, Morillo, Ginkel, Thompson, Loáisiga, Clarke, and Garcia—have carried 75% of the load with an impressive 2.51 ERA and 3.41 SIERA. Only Sewald's 3.47 ERA sits above 3.00, and the 36-year-old closer has converted 15 of 16 save opportunities. These arms are young, efficient, and mostly healthy right now. That's the trap.

Diamond backs starters are averaging just under 5⅔ innings per game, a pace that is neither sustainable nor accidental. Michael Soroka is running hot, but he threw only 89⅔ innings last season (his first full-time starter work since 2019) and is already approaching that workload with weeks to go. Corbin Burnes, the 2021 NL Cy Young, is sidelined until September with a teres major strain and won't contribute. Eduardo Rodriguez carries a 4.57 SIERA despite his 2.52 ERA—a classic xFIP/ERA divergence signaling regression ahead. Merrill Kelly, Zac Gallen, and Ryne Nelson round out a rotation that can provide innings but not necessarily quality innings as the summer grind deepens. Hazen is hoping Brandon Pfaadt regains form in Triple-A, but that's hope masquerading as planning. The math is straightforward: if starters keep averaging 5⅔ innings, relievers will accumulate 250+ innings by season's end. That core group of seven arms will face significant wear-and-tear. Even if Hazen adds one "back-end arm" (his phrasing), Arizona will need depth volume, not just elite relief. A.J. Puk and Justin Martinez have been sidelined for over a year and cannot be counted on.

For prop bettors, this creates a specific vulnerability in the second half. Arizona's team totals and run-line outcomes will carry elevated variance after late July, when relievers begin showing fatigue and starters are forced to pitch deeper into games to rest the pen. Hitters who feasted on a fresh bullpen in June will face a thinner margin for error by August and September. Conversely, any Diamondbacks reliever entering games in high-leverage spots (save situations, inherited runners, RISP contexts) becomes a short-window fade after the trade deadline passes without a marquee bullpen addition. Sewald, despite his 15-for-16 save rate, will see pitch counts spike and effectiveness decline. This isn't a linear fade—it's a time-stamped one. The window for backing Arizona's bullpen-reliant under scenarios (team total overs, game overs, individual reliever strikeout props) closes materially after late July. Buy now, before Hazen's roster limitations catch up to the standings.