The Diamondbacks Can Use Rotation Depth to Their Advantage

The Arizona Diamondbacks are coming off a tough-to-swallow 2024 campaign in which they saw great success and yet failed to make the postseason in a packed National League playoff picture.

Their record of 89-73 is indicative of how good they were this year, but some parts of their roster let them down a bit. Just a year removed from a National League pennant, what did the Dbacks do different this season?

To start, they came out of the gate in 2024 with simply alright success but not to the same extent that they had in the 2023 postseason. In the Diamondbacks’ first half of the season, they finished with a record of 49-48, putting them just a hair above the .500 mark and in third place in the NL West.

Their best success came in the latter half of 2024, when they blitzed out a 40-25 second half record, coming incredibly close to a playoff berth but barely missing out.

In the offseason heading into the 2025 season, there are some extra pieces that Arizona could move on from.

Starting Depth

The Dbacks had 14 different pitchers start games in 2024, but not necessarily owing many starts to an ‘opener’ role. Aside from their four rotation regulars who started 20+ games this year, Merrill Kelly and Slade Cecconi started 13 apiece, Eduardo Rodriguez made 10 starts, Tommy Henry made seven, and Blake Walston started a pair of his own.

All five of these pitchers have made the majority of their career MLB appearances as starting pitchers, aside from Walston who is one of the Diamondbacks’ top pitching prospects and got his first taste of MLB action this year.

Arizona can sit comfortably on a five-man rotation of Brandon Pfaadt, Zac Gallen, Ryne Nelson, Rodriguez, and Kelly for the upcoming season and expect consistent success. Don’t forget about that Jordan Montgomery guy, too, but his status is very much up in the air right now.

All five of these starters, given healthy slates for them all, could sufficiently lead this team to plenty of wins in 2025.

This just goes to show that Arizona has plenty of arms to spare. The majority of these pitchers are younger than 30 years of age, so their trade value might be nearing its peak in some of these cases.

Places For Improvement

There are two prominent places where the Diamondbacks’ outlook to 2025 is rather rocky: first base and the bullpen.

While for different reasons, both of these positions can certainly be helped via offseason trades.

If Arizona can make some moves to bolster these parts of their roster, they’ll cement themselves as a force to be reckoned with in the NL.

First Base

First base in Arizona has been manned full-time by slugging and slick-fielding Christian Walker since 2019 and his status as a free agent leaves some uncertainty at the position. Walker ranks as the top first baseman on the market and rejected a $21.05 million qualifying offer from the Snakes earlier this offseason.

They also had switch-hitter Josh Bell man the position for 31 games after acquiring him at the trade deadline, but he is also a free agent this offseason. Arizona could slide utilityman Pavin Smith to fill the lineup spot with his 142 wRC+ in 2024, but his defense pales in comparison to Walker’s.

FanGraphs ranked Walker as the top first basemen in all of MLB this past season in UZR (Ultimate Zone Rating) and slightly behind Carlos Santana in OAA (Outs Above Average). Walker and Santana both won their respective league’s Gold Glove award in 2024.

The potential loss of one of the most valuable first basemen in baseball leaves a sizeable hole in the Diamondbacks’ lineup, as his 119 wRC+ ranked second on the team behind the National League’s 3rd-place finisher in MVP voting in Ketel Marte.

The Dbacks could either pursue a re-signing of Walker or try to grab another good first basemen through a trade.

Losing Walker would be a big blow to this lineup, so they’re going to have to fill the gap somehow. A trade for Cody Bellinger or Alec Bohm could give them a solid option to replace the offense that’s likely leaving on the open market.

Bullpen

Arizona’s bullpen was simultaneously one of the strongest parts of their team and one of the worst. One one hand, their pen boasted four relievers with 59+ innings pitched and a sub-4.00 ERA, those being Justin Martinez, Kevin Ginkel, Ryan Thompson, and Joe Mantiply.

At surface level, these individual performances might seem to show that Arizona’s pen was very strong in 2024.

However, these relievers only make up 268.2 innings of the 617.0 innings the entire Arizona bullpen threw across the 2024 season. The Diamondbacks’ bullpen as a whole chalked up a 4.41 ERA, ranking 26th across all of MLB.

Their deadline additions of lefty A.J. Puk and righty Dylan Floro cancelled each other out fairly well, as Puk notched an excellent 1.32 ERA over 27.1 innings of work while Floro struggled; managing to post a 9.37 ERA over 16.1 innings.

Arizona finished tied for sixth league-wide in blown saves with 26. One has to imagine that if they would have been able to convert a few extra saves, they would have landed squarely in the postseason bracket.

As a whole, the Dbacks could certainly use an improvement on the back end of their pitching staff and this offseason is the time to do it.

Who Could Be Traded?

The most obvious name to be traded is the left-handed Montgomery, who recently made the complicated decision to accept Arizona’s $21.05 million qualifying offer for the 2025 season.

This move spites Dbacks owner Ken Kendrick, who was outspokenly regretful of Arizona’s two-year, $47.5 million commitment to the veteran hurler made in the previous offseason.

This provides plenty of reason why the Diamondbacks might be looking to move on from Montgomery, as if his 2024 performance wasn’t enough already.

Montgomery posted a ghastly 6.23 ERA across 117 innings while striking out a career-low rate of 6.4 batters for every nine innings of work. This season was certainly an career outlier for Montgomery, but it would be risky for Arizona to take a chance with him in the rotation if they want to compete.

“Monty” is definitely a valuable pitcher, though, and there are multiple teams that could benefit from his services despite a high price tag.

Other than Montgomery, Arizona’s expendable arms in their rotation depth are likely to be Henry, Cecconi, and potentially a name like Kelly if things go sideways.

Henry has a great curveball and changeup but struggled in a limited role in 2024, Cecconi has yet to get his feet fully under him at the MLB level but has amazing control, and Kelly is a seasoned vet with incredible upside that could be a valuable trade piece if he’s made available.

No matter who gets traded out of Arizona’s rotation depth pieces, this offseason will be incredibly important to this team’s success in 2025. They were good this past season but came up short of the postseason, but who’s to say they couldn’t get there next year with a few more pieces?