Arizona Diamondbacks – Projected rotation check in

Opening Day’ ‘s fast approaching. We’ve had a good look at the pitchers over Spring, and we thought it’s time to reflect and do a check-in on some projected starting rotations. We take a look at the Diamondbacks’ projected rotation today.

SP1: Zac Gallen

The Milkman is delivering early this spring.

Zac Gallen’s 2026 Spring Training has been a masterclass in “trust the process.” After a late arrival to camp following his re-signing with the D-backs, he hasn’t missed a beat.

The most encouraging sign? The heat. Gallen’s heater averaged 94.7 mph in his debut—over a full tick up from last year. When Gallen is sitting 94-95 with that elite command, hitters should be on notice.

His Spring so far:
⚾️ 3 Starts | 6.2 IP
⚾️ 4.05 ERA | 1.20 WHIP
⚾️ Fastball velo up 1.2 mph from ‘25

He’s spent his last few outings experimenting with the sinker and changeup consistency. Even with a rocky line against the Giants (3 ER in 2.2 IP), the focus has been on shape and repeatability over results. He’s already signaled that his final spring tune-up will be treated like a full-go regular season game.

With Merrill Kelly sidelined, Torey Lovullo has officially tapped Gallen for his 4th consecutive Opening Day start. From free agent uncertainty to the tip of the spear in the rotation, Gallen remains the anchor this team needs.

It will be interesting to see if Gallen’s increased velocity this spring will lead to a higher strikeout rate in the 2026 regular season.

SP 2: Ryne Nelson

Nelson has entered the 2026 spring training season with a secured spot in the Arizona Diamondbacks’ starting rotation, a significant shift from previous years, where he battled for the fifth starter role. This stability follows a breakout 2025 campaign where he posted a 3.39 ERA and a 1.07 WHIP over 154 innings.

Nelson is actively working to decrease reliance on his four-seam fastball, which he used over 60% of the time in 2025. He has shown an improved, harder slider in the mid-to-upper 80s and is mixing in a curveball and cutter more frequently to keep hitters off-balance.

His Spring results have not been good, however this might actually be a case of “spring results don’t matter and here’s is why:

1. The “Hard” Slider is Real
The biggest knock on Nelson has been his 60%+ fastball usage. This spring, he’s refined a harder slider (mid-to-upper 80s) that’s already generating whiffs. He’s becoming a true pitcher, not just a “thrower.”

2. Elite Control
8.0 IP, 10 K, and only 1 BB. A 0.75 WHIP tells the real story. He’s pounding the zone and forcing contact, even if a couple of homers in his last outing against the A’s inflated the ERA.

3. Durability is the Goal
After “shocking his system” with a heavy workload last year, Nelson spent the winter getting stronger. With Corbin Burnes out until mid-season, the D-backs need 180+ innings from Ryne. He looks physically ready for the grind.

4. The Potential Ceiling 
If the secondary pitches (slider/cutter/curve) continue to keep hitters off that elite 96-97mph heater, we aren’t just looking at a mid-rotation stabilizer—we’re looking at a potential front-line starter.

Ryne Nelson could be primed for a massive year in the desert.

SP3: Eduardo Rodriguez

The Eduardo Rodriguez “Revenge Tour” might actually be loading in Arizona.

After a frustrating, up-and-down 2025 (5.02 ERA), E-Rod didn’t just show up to camp—he showed up as a different person. Down 23 lbs, the veteran lefty is looking as explosive as we’ve seen him in years.

The early Spring returns for the Dbacks:

• The Velocity Jump: His fastball averaged 93.1 mph in his debut, peaking at 95. That’s a massive tick up from his 92.0 mph average last season.
• The “True” Curveball: He’s scrapped the inconsistent slider for a refined curve that’s already inducing weak contact and higher whiff rates.
• WBC Dominance: Just last week, he carved through a loaded Dominican Republic lineup, racking up 5 K’s in less than 3 innings.

With Merrill Kelly’s health in question and the rotation needing a high-floor anchor behind the big guns, a healthy, “best-shape-of-his-life” E-Rod changes the ceiling for this Diamondbacks staff.

SP4: Brandon Pfaadt

Brandon Pfaadt is sending a CLEAR message this spring: The 2025 “sophomore slump” is officially in the rearview mirror.

Through 10 innings in the Cactus League, the D-backs righty is putting up video game numbers:
🔹 0.90 ERA
🔹 0.60 WHIP
🔹 11 K / 3 BB
🔹 Only 3 hits allowed

But the stats don’t tell the whole story. It’s about HOW he’s doing it.

Last year, Pfaadt struggled with his sweeper—a pitch that was once his bread and butter but became a liability in ’25. This spring, he’s made mechanical adjustments to his delivery, focusing on staying through the zone longer.

The payoff? In his last start vs. San Diego, he was untouchable:
5 IP, 0 H, 0 BB, 6 K
43 strikes on 51 pitches
40%+ whiff rates on both his sweeper & changeup

With Corbin Burnes out until mid-season, Arizona desperately needs a reliable arm behind Gallen. Pfaadt isn’t just looking like a rotation filler; he’s looking like the frontline starter the front office bet on with that $45M extension.

If this refined pitch mix holds, Pfaadt is the premier breakout candidate in the NL West for 2026.

SP5: Michael Soroka

The Michael Soroka “Redemption Arc” is officially in its most fascinating chapter yet.

After a rollercoaster few years, Soroka entered Diamondbacks camp this spring with a modified delivery and a mission to prove he’s still the 2019 All-Star we remember. Here’s the deep dive on what we’ve seen so far in 2026:

1. The Velocity is BACK 
Forget the 92-93 mph of years past. In his WBC outing against Colombia, Soroka was letting it rip, averaging nearly 95 mph and hitting 97 mph on the gun. That kind of heat, paired with his heavy sinker, makes him a completely different animal than the version we saw in 2024-25.

2. The New Weapon: The Cutter 
One of the most encouraging developments is the 90-91 mph cutter. He’s using it to bridge the gap between his high-velocity heater and his 82 mph curve. When it’s on, it’s a legitimate out-pitch that helps him navigate through lineups a second or third time.

The Bottom Line:
Soroka is throwing harder than he did during his peak years in Atlanta. If he can harness that 97 mph heat and refine the command of his new cutter, he isn’t just “rotation depth”—he’s a potential front-line starter waiting for his opening.

Arizona took a $7.5M flier on him. If this Spring is any indication, they might have found the steal of the offseason.