Extension candidates for the Arizona Diamondbacks to consider
The Arizona Diamondbacks have a handful of extension candidates. from young players that they could secure long term, and veterans approaching free agency.
Some of the Arizona Diamondbacks’ players could receive an extension in the near future. Many of their key players are nearing free agency. The last big-time extension the D-Backs handed out was to second baseman Ketel Marte, who signed through 2027 at $76 million right before the start of the 2022 season. But the Diamondbacks have a handful of young players that they could secure to long term deals now, as well as veteran players who are within eyeshot of free agency. There are plenty of players that the Diamondbacks should try and lock down now.
Position players
If the Diamondbacks do not sign Christian Walker to another contract, he will be one of the best free agents on the market next off-season. Over the last two seasons, the first baseman is batting .250/.330/.487 with 69 home runs, and a 122 wRC+. Walker has a quality 9.9% walk rate and 19.4% strikeout rate while having a .237 isolated slugging percentage. Walker is a two-time Gold Glove winner, and deservingly so. Over the last two years, he has +26 defensive runs saved and +26 outs above average. He’s not just the best defensive 1B in baseball, but ranks top five among all players in baseball in both stats.
Signing Walker to an extension could be an extremely good move. But one thing to keep in mind is that he turns 33 in about a month, and his first year of a new contract will be his age-34 campaign. A new contract for Walker could look something like what Josh Donaldson signed with the Minnesota Twins a few years ago, who signed a four-year deal at $92 million. Donaldson had a similar 131 wRC+ in his age-33 season. The length seems about right, but Walker’s total salary might be slightly lower, given he’s a year older than Donaldson was. As of right now, there's reportedly not been "too much" talk between the two parties, according to Nick Piecoro of the Arizona Republic.
It would be nice if the D-Backs could tie catcher Gabriel Moreno down to a long-term deal now. Moreno’s first full big league season went great, as he batted .284/.339/.408 with a .325 wOBA and 103 wRC+. Moreno did not hit for much power, with only seven homers and a .123 isolated slugging percentage. His 7.6% walk rate was slightly below average, but he struck out less than 20% of the time at 19.7%. Moreno showed off some good defensive prowess with +20 defensive runs saved, +10 blocking runs, and a 1.90 pop time, but -3.9 framing runs. He was even better in the second half of the season, batting over .300 at .313 with an OPS approaching .900 at .894.
Moreno just turned 24 earlier this month and is still a whole two seasons away from arbitration. But you probably wouldn’t find a Diamondbacks fan opposed to buying out his arbitration years, along with some of his free-agent years. Signing him now could give the D-Backs a major bargain. However, Moreno could also be waiting it out for the same reasons, as he could try to bet on himself.
But if there was any young player that you’d love to see the Diamondbacks secure to a long-term deal now, it would be outfielder Corbin Carroll. Carroll is coming off the best rookie season in Diamondbacks history, as he batted .285/.362/.506 with a 133 wRC+. However, his power/speed was nearly unparalleled by anyone as young as him. He went yard 25 times with a .221 ISO and stole 53 bases, making him the only rookie with 20+ homers and 50+ SBS. Carroll’s glovework received solid reviews. While DRS had him at -3, OAA pinned him at +4. His best defensive work came in the outfield corners.
Securing Carroll to something like a ten-year contract would do wonders for the Diamondbacks. This is their most talented player since Paul Goldschmidt. It might not be cheap to extend Carroll, but the Diamondbacks should totally consider it sooner rather than later. He’s definitely someone you want to build around long-term.
Pitchers
Zac Gallen would be at the top of my list. Gallen has now finished in the top five in Cy Young voting two years in a row. He has pitched 394 innings in the last two years, the 8th most in baseball, working to a 3.04 ERA, 3.16 FIP, and 1.02 WHIP. Gallen strikes out a healthy amount of batters with a 26.9% K-rate but has an even more impressive 6% walk rate. Home runs haven’t been much of an issue either as the right-hander has had a 0.85 HR/9 rate since the outset of the 2022 campaign.
Gallen is heading into his age-28 campaign but is in his next to last year of control. 2025 marks his final year of arbitration before he heads into free agency. His first free-agent season will be his age-30 campaign. If Gallen reaches free agency, his contract might look something like Carlos Rodon. Rodon also signed a long-term six-year/$162 million deal with the NY Yankees prior to his age-30 season. Rodon had +10.5 bWAR in his two years prior to heading into free agency. Gallen has +9.6 bWAR in the last two seasons. If the D-Backs start negotiating before he hits FA, they might get him for something closer to $150 million.
Merrill Kelly is another large rotation cog that is soon to hit free agency after the 2025 season. The D-Backs hold a club option for 2025 worth $7 million, and so long as nothing catastrophic happens to Kelly in 2025, it will assuredly get picked up. Kelly has also been extremely effective the last two seasons with a 3.34 ERA, 3.85 FIP, and 1.16 WHIP over his last 378 frames. He has a respectable 23.8% K-rate, 8.5% walk rate, and 0.98 HR/9. He has posted back-to-back +3.0 bWAR and fWAR seasons.
Kelly is older than Gallen, as his first year after signing a new contract will be his age-36 campaign. However, he’ll definitely land a deal if he's still effective. At that age, he might have to settle for a one-year guarantee, but with the rest of the years being option/buyout seasons. I could see a one-year deal with the second and third years as team options.
Extending Brandon Pfaadt now might be a good idea. The right-handed headed into August with an 8.20 ERA, 7.22 FIP, and 1.63 WHIP. The only good thing to say about his first handful of outings was his 6.4% walk rate. Pfaadt had struck out just 17.5% of the batters he faced, with a HR/9 rate over 3.00 at 3.13. However, from that point forward, Pfaadt had a 4.14 ERA, 3.89 FIP, and 1.26 WHIP. He lowered his BB% to 6% while upping his K% to 25.6%. His HR/9 also returned to Earth, settling at 1.38. Pfaadt then pitched extremely well into the playoffs.
It would be a good idea to try and take advantage of Pfaadt’s so-so rookie season. Signing him to a low-cost extension would be great. But like I said with Moreno, Pfaadt might not be willing to negotiate an extension right now for the same reasons. But Pfaadt and Gallen could be a very good and homegrown 1-2 punch for the Diamondbacks for years to come if they extended both players.
As of right now, the only relievers that would be worth considering signing to extensions are Paul Sewald and Kevin Ginkel. Sewald is a free agent after this season. He’s been a quality closing pitcher now for the last three years. Ginkel had an outstanding 2023 breakout campaign and became the go-to set-up man for the Diamondbacks. He is under control via arbitration for three more seasons.