What went wrong on the mound and how can it be fixed?
One of the main reasons we aren’t currently watching the D-Backs vie for the Commissioner’s Trophy right now is because of the mediocre pitching the team received this year. At first blush, that may seem somewhat harsh, but considering the team boasted the second-best offense in the National League and the second-best offense in the entire majors, and still didn’t qualify for the postseason, it is the reality. It’s particularly galling since those two phenomenon were flipped the prior year when a league-average offense was buoyed by an equally average pitching staff that went on an incredible tear in the playoffs. Encouragingly, the front office and ownership saw the weak areas in the team and sought to augment them through a variety of acquisitions. Instead, the two highest profile acquisitions to the starting rotation took substantial steps back this year as the team fell just short of qualifying for a consecutive postseason for the first time in 22 years. That maddening regression between seasons is the leading reason why Brent Strom lost his position and the team will be looking for answers heading into a pivotal offseason and season.
I am still agnostic on what, if any, effects a pitching coach has on performance, but that’s a topic for another day. Of course, in a perfect world, 2025 would be the “Goldilocks” season wherein the pitching takes a step closer to what they were in 2023 while the offense maintains some of the incredible potency they possessed from June to August. Unfortunately, that sort of good luck rarely occurs in baseball and it’s just as likely that the offense as a whole takes a step back – especially if something like Ketel Marte’s MVP-caliber play turns out not to be fully sustainable. So, if the team wants to return to the postseason in 2025, the hurlers will need to take a step forward and you can look no further than the starters for the first real test of that hope. The starting rotation this year was particularly egregious – although the relief pitching left something to be desired as well – with a -4.9 bWAA which was second-worst in the National League. In the previous season, the rotation was merely average with a -1.0 bWAA that put them squarely in the middle of the National League. What happened and how can the team fix it? Let’s focus on the starters for now since the relief corps is a little on the messier side.
Zac Gallen
In many ways, the Arizona rotation begins and ends with Gallen. That may seem overstated, but he has been the staff ace since joining the rotation full-time during the COVID-shortened season in 2020. Since that season, he has been one of the most valuable starters (by bWAR) in the league and beating out luminaries like Aaron Nola, Framber Valdez, and Shohei Ohtani. That’s why it was so disconcerting to see the righty stumble as much as he did this year – at least compared to his lofty standards. I suspect some of those stumbles are a direct result of the long postseason run last year, but he was not the same pitcher after his monthlong IL stint this year. Before going on the IL at the end of May, he had posted an excellent 3.12 ERA and 1.14 WHIP across his first 11 starts, but those numbers ballooned to 3.99 and 1.34 respectively across his final 17 starts. This upcoming season is his platform season with free agency looming in the 2025 offseason – it would go a long way for him and the team if he can return to his ace form.
Merrill Kelly
If Gallen has been the starting equivalent of Batman for the D-Backs, that might make Kelly the Robin in this metaphor. The duo have been rotation-mates for nearly five years and the senior member is just a couple ticks below where Gallen is on the above list of most valuable starters since 2020. As Jim excellently summarized in his piece about pending options for both player and team, Kelly has to be one of the most valuable signings by AAV for Mike Hazen. Frustratingly, he struggled to stay on the field in 2024 with a length three and a half month stint on the IL for a shoulder strain and multiple starts shortened with cramping issues. When he was on the bump, he certainly had flashes of the kind of stability he’s provided in prior years, but he also had multiple clunkers – including the opening of the team’s final series of the regular season when he allowed five runs on eight hits and took the loss. His contract option is an easy one for the team to pick up because of his track record and they don’t necessarily need him to be a number-two option in the rotation for the team to succeed, but they do need his dependability as this year tragically demonstrated.
Eduardo Rodriguez
One of the big-name free agent acquisitions by Hazen in the offseason, Rodriguez struggled to get on the field as his team debut didn’t come until the beginning of August, and even when he did, he failed to find much traction. The veteran lefty struggled with his control as he failed to have a single outing without allowing at least one walk and gave up five or more hits in eight out of his ten starts. It’s difficult to summarize the results as anything less than extremely disappointing after the southpaw’s breakout performance in 2023. If the team has any hope of returning to the postseason in 2025, Rodriguez will need to rediscover that form and step into a number-two or three role in the rotation while providing some leadership. One key to that hope will be finding what changed for his fastball and changeup in the offseason. They were two of his most effective pitches last year by run value, but completely fell off this year.
Brandon Pfaadt
This has to be one of the most confusing parts of this season: after a disappointing regular season last year, Pfaadt went on one of the best postseason runs in franchise history -including out pitching Batman from above. It’s certainly possible that it was just small sample size, but it significantly boosted Pfaadt’s overall stock in the eyes of fans and evaluators alike and put him in line for a significant step forward this year. Instead, the young righty turned in a middling season where he failed to take the next developmental step forward that the team thinks he’s capable of taking. While I’m still unconvinced about how coaching can affect intragame results, Pfaadt’s developmental regression this year is undoubtedly an indictment on Strom’s leadership and coaching acumen. In my mind, Pfaadt has proven he’s capable of moving into the next tier of starters, but now it’s about demonstrating that capability consistently. He showed flashes of it this year amidst the muck – like a seven inning gem in Milwaukee where he allowed just one run and racked up a dozen strikeouts just five days after allowing eight runs in 1.2 IP to the same team. Now the question becomes: which Pfaadt is the real one?
Jordan Montgomery
The other free agent signing from the offseason, it’s fair to characterize as an epic failure given the discrepancy between expectation and reality. There was little that went right for Montgomery in his first year with the D-Backs, which means that if you’re the optimistic type, the performance can only go up from here!
Ryne Nelson
Conversely to Pfaadt’s forgettable 2024 season, Nelson’s breakout season ranks as one of the best storylines from the team this year. Following a disappointing 2023 campaign that saw Nelson bounce between the bullpen and rotation, it looked as if the Nevadan may get squeezed out of the latter with the Montgomery and Rodriguez signings as well as the possible emergence of Pfaadt. Instead, with the rotation decimated by injuries, Nelson slotted into the number-two or three slot for part of the season and stuck even as those injuries subsided. Part of the reason: for two months of the season, he was the team’s undisputed ace as he pitched to a 2.77 ERA and 0.98 WHIP across ten starts from the beginning of July to the end of August. If you expand out slightly, he had a respectable final three and a half months, posting a 3.59 ERA and 1.07 WHIP from the beginning of June until the end of the season – including two starts bookended by injury in September. I’m inclined to believe (or hope) that this is a durable change from the youngster that would go a long way towards lengthening the rotation.