What Kind of Haul Could Zac Gallen Get?

As everyone saw on Thursday evening in the Josh Naylor trade (and then Randal Grichuk last night), the Arizona Diamondbacks are official sellers, though they still could buy a player or two that has control.

Overall, though, they will be selling, and some reports say it could be up to six or more players. That’s due to the fact that the D-Backs have so many expiring contracts at the end of the season. One of them is former ace Zac Gallen.

The Diamondbacks are open to selling many players, including Gallen, who was supposed to be one of the two aces on the team in 2025. Unfortunately, he has had the worst season of his career, with some highlight games, but generally an arm that Arizona hasn’t been able to rely on.

However, he’s not far removed from being an All-Star caliber pitcher with multiple top-five finishes in the NL CY Young voting. After all, from 2021 to 2024, Gallen had an ERA of 3.41 and a FIP of 3.41 with 197 walks and 707 strikeouts in 663.1 innings.

While that’s a far cry from his rate stats of a 5.58 ERA, 4.86 FIP, 46 walks, and 116 strikeouts in 121 innings, he has made every single start this year and looks to be able to finish the season without missing a start. Plus, his FIP is nearly a full run lower than his ERA, and his xFIP is an even better 4.09.

That would indicate that some of his ERA issues and run prevention issues are on the defense and just bad luck in general. However, he’s had major issues preventing the ball from leaving the yard as he’s already given up a career-high 23 homers, which leads the league.

Despite that, Gallen still has the ability to get outs effectively and pitch deep into games. His walks per nine innings are essentially the same as 2024, when he had a 3.65 ERA, as in 2024 it was 3.3 and this year, it’s 3.4. He’s had 11 starts with six or more innings, something that will be noticed by contenders. That’s over half of his 21 starts so far this year.

Many contenders will see him as a No. 3 or 4 starter for their rotation with high upside if they are able to unlock him or fix his delivery and get him back to how he was before this season. His pedigree will raise his value to teams, along with the fact that he’s a rental starting pitcher. Those prices are already high, and every contender could use a starter with the potential that Gallen has.

That’s why it won’t be a surprise if a team pays up for Gallen and gives an offer far better than the Qualifying Offer pick Arizona would get in the off-season. If that happens, general manager Mike Hazen will have to bite on it. After all, it’s unlikely Arizona will re-sign Gallen, and getting some upper-level prospects for Gallen would help the team compete in 2026 and beyond.

This could be a rare occasion when a team acquires a player that provides a big return over just two months and the playoffs just due to a different environment, as Gallen looks like a prime change-of-scenery candidate. It will likely take a prospect around the back-end of the top-100 or shortly beyond it, and another medium-upside prospect to get him.

What Could Teams Offer the D-Backs For Zac Gallen?

Chicago Cubs

The Cubs have plenty of prospects that would entice the Diamondbacks. Some are far too valuable to give up for just Gallen, while others are in the sweet spot where if everything goes right, the headliner of this deal could sneak his way into the back-end of the top-100, but isn’t currently a top-100 guy as he just missed out in this writer’s opinion.

The headliner is James Triantos, a second baseman and outfielder who has displayed plenty of potential and the chance to be a good regular in MLB once he makes it. Triantos is already in Triple-A and fits what Arizona is looking for as an upper-minors player.

He’s a strong contact bat with plenty of speed, though the power leaves much to be desired. Pair him with Will Sanders, a right-handed Triple-A pitcher who might make it to the Majors as a No. 5 guy, and Arizona likely takes the deal while Chicago isn’t hemorrhaging its future to get a high-upside rental.

Toronto Blue Jays

The Blue Jays have been rumored to be in the market for Gallen and especially a starting pitcher. Gallen shouldn’t cost them too much compared to some of the pitchers on the market while possessing perhaps more upside than any of them.

Giving up Gage Stanifer, a High-A starting pitcher from the right side, would be the main focus on the deal. He’s 21 with a strong fastball/slider combination that has led to him striking out 103 batters in just 65 innings, but he has walked 37.

When he commands his pitches, it’s very tough to get a hit on him, but he has been a bit prone to losing command. He has the makings of a mid-rotation starter if he can hone his command and continue to build out his innings.

The Blue Jays could pair him with Lazaro Estrada, a right-hander in Triple-A. Estrada has already made his MLB debut and could slot in for the Diamondbacks in their starting rotation fairly quickly, albeit not near Zac Gallen’s ability. Estrada throws strikes and would be ready for MLB action this season, something Hazen wants.

New York Mets

The Mets likely aren’t giving up any of their vaunted pitching prospects, but they do have a prospect that likely fits Arizona in their No. 7 prospect, Ryan Clifford, who plays first base and outfield.

The D-Backs have a long-term void at first base. Clifford has elite power and is already in Double-A. He has an .830 OPS and 35 extra-base hits, including 19 home runs. He could be ready for the Majors by mid-season in 2026 and take over at first base.

The Mets could dangle a pitcher in the form of Dom Hamel, who is in Triple-A to get the deal done. Hamel can start or pitch in relief from the right side. So far in Triple-A, he has a 4.56 ERA over 49.1 innings, but has struck out 55 to just 15 walks.

Boston Red Sox

The Red Sox have a couple of pitchers that likely intrigue Arizona’s front office. While they won’t get Payton Tolle, they could get David Sandlin, a right-handed starting pitcher. He’s 24 years old and in Double-A with the projection to debut next season.

He would give Arizona another valuable upper-minors starter to finish developing. He has a 3.61 ERA in 82.1 innings with 86 strikeouts and 27 walks. If they can finish his development, he has a chance to be a top-three starter in the rotation.

Arizona would likely ask for one more piece to round out the trade, and Boston could offer Blake Wehunt. He’s a right-hand pitcher also in Double-A that starts. He has less upside than Sandlin but is projected to debut next year as well and has shown the ability to stay in a rotation long-term.

Houston Astros

The Astros’ farm system is a little barren due to the injuries they’ve suffered this year and the call-ups they’ve relied upon. That means it would take a higher prospect in order to snag Gallen. Their top pitching prospect would likely be Miguel Ullola.

He’s in Triple-A and is a starting pitcher. His fastball is extremely tough to hit, but he still needs to refine his secondaries to be a legitimate MLB starter. The other issue is control in which he might wind up being a late-inning reliever if he doesn’t improve.

The Astros could pair him with Juan Bello, a High-A right-handed pitcher. He’s a starter and reliever who has a four-pitch mix and could stay in the rotation if he can hone in his command. Otherwise, he has a late-inning reliever in him who could reach the majors in a couple of years.

It’s not known yet if Arizona will trade Zac Gallen. The Arizona Diamondbacks can offer him the Qualifying Offer and get a draft pick in return once he signs elsewhere. That means that teams will have to beat the value of that pick if they hope to get him on their roster to end the 2025 season.