Since the MLB trade deadline, Zac Gallen has been pitching far better than he did in the first half for the Arizona Diamondbacks. He’s been one of the reasons why Arizona has climbed up from 10 games back in the Wild Card chase to just two games back. He’s also setting himself up for free agency at the end of the season.
Entering the 2025 campaign, the Diamondbacks needed Gallen to pitch like an ace, as he did in 2022 and 2023, when he finished among the top NL Cy Young vote-getters. However, 2024 saw him take a step back, albeit while still finishing with a decent 3.65 ERA over 148 innings.
Instead, over the first half of 2025, the floor broke, and Gallen fell into dire straits, getting hammered for home runs and having by far the worst start to a season of his career.
Over his first 22 starts from March to the end of July, Gallen slumped to an unsightly ERA of 5.60 with a high FIP of 4.80. That was over 127 innings with 121 strikeouts, 125 hits, 47 walks, and a mammoth 23 home runs. He just couldn’t locate his fastball in the strike zone consistently and had a problem with avoiding slug.
However, after the trade deadline, when it was clear that Gallen was staying with Arizona and the pressure decreased across the team (as it became extremely likely they would miss the playoffs), Gallen rounded back into his 2022-23 form.
From August 2 to September 3, Gallen was a legit ace once again, excelling against all facets of teams and leading Arizona to one of the best records in MLB as they clawed their way back into the thick of the Wild Card race.
Over these seven starts and 41 innings, Gallen pitched to a 2.20 ERA and 3.22 FIP. He allowed only 33 hits and 10 runs with 10 walks against 33 strikeouts. He was challenging hitters in the zone, attacking consistently with his fastball, and looked every bit like the bulldog he was in years past, ahead of a critical free agency offseason.
The D-backs went 5-2 in these starts, and Gallen pitched six innings in six of them, earning a quality start in all six of those outings.
However, this past Tuesday, against the San Francisco Giants, in a true must-win game for Arizona to gain huge ground in the Wild Card race, Gallen still pitched 6.2 innings but faltered. He got hit hard again, allowing two home runs despite giving up only three in his previous seven starts.
He gave up five runs, three walks, and five hits with only three strikeouts. The Diamondbacks’ offense wasn’t able to make up the five-run deficit, and Arizona fell a game behind the Giants in the Wild Card standings below the Mets, who lost Tuesday as well.
Now, there’s still time for both Gallen and Arizona to finish the season strong and potentially have a 2023-esque miracle playoff run, as they are only two games back. Gallen next pitches tonight, September 15, when he can get revenge against those Giants.
Then, assuming Arizona doesn’t change the rotation, he’ll get two more starts, against the Philadelphia Phillies and San Diego Padres, to finish the season on a strong footing and prove to MLB teams that he deserves the contract he will be seeking in the offseason. Plus, it gives him three more chances to help Arizona get into the playoffs.
Assuming Gallen finishes fairly well over these last three starts, he will be an extremely interesting free agency case study, considering his high ceiling and low floor. It’s difficult to gauge what teams will be willing to pay him ahead of his age-30 season.
Gallen’s agent, Scott Boras, is known as a tough negotiator who seeks high dollar for his clients. This often leads to his clients staying on the market quite a while, and some of them, especially pitchers, have wound up signing short-term deals with opt-outs that allow them to re-enter the market after a better platform season.
Or, sometimes, Boras is able to get a big money deal like he did this past offseason for Blake Snell, who signed for $182 million (with deferrals) over five years after a one-year platform season with the Giants.
Although Gallen has 20.8 bWAR so far in his career, he’ll be entering free agency off a season of just 1.2 bWAR (as of today). FanGraphs lists him at just 17.4 fWAR in his career and only 0.9 fWAR for this season.
That kind of platform season could serve as a justification for teams to avoid paying the long-term, high-dollar contract that Gallen and Boras will be seeking, despite him being fairly healthy and productive over his seven-year MLB tenure.
That could lead him to decide to take a short-term pillow-like contract, such as the deals Snell and Jordan Montgomery signed after the 2023 season, when they were left on the market until February or March. This is quite possibly the most likely scenario for Gallen, as it’s pretty certain he’ll stay on the market for a while, given Boras’ history with pitchers like Gallen.
However, it takes just a single team to make an offer that Gallen and Boras would accept. In that scenario, Gallen won’t be the $35 million AAV pitcher that he was shaping up to be after 2023. But, with his track record, he’s more than a $20 million AAV pitcher, if 2025 turns out to be just a badly timed down year.
So, he could perhaps find his way to an Aaron Nola-esque deal. Nola got seven years at $172 million for a $23 million AAV in the 2023-24 offseason. Nola is a fairly close comp, in that he was a good No. 2 starter at the time, and Gallen is likely going to be a good No.2/3 should he continue rebounding.
However, if Gallen opts for a shorter deal, say three or four years with opt-outs, he might be able to secure an AAV in the $25 range, as Nathan Eovaldi earned last offseason and Sonny Gray did the year before. This would allow him to get the elusive and enticing higher AAV, but it could also get him back on the market sooner to get another big free agent contract in his early-to-mid-thirties.
At the end of the day, it’s a true guessing game because Zac Gallen is an established veteran pitcher who has been healthy arm-wise, was effective for numerous years, once took a no-hitter deep into a World Series game, but is grinding through a difficult walk-year.
The Arizona Diamondbacks will likely give him a qualifying offer, which will cost the team that signs him a draft pick. That will affect his market, limiting it to a certain degree.
That’s just one more issue that Gallen and Boras will have to overcome in free agency, and it’s always possible the Diamondbacks themselves bring him back on a pillow deal. However, it all depends on how he finishes over these last three starts. If they go well, it’ll go far in making teams think his first half was an aberration.
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