MLB Mock Blockbuster Trade: Arizona Diamondbacks Deal Zac Gallen To New York Mets

In this MLB mock trade, the Arizona Diamondbacks send ace Zac Gallen to the New York Mets in a bold deadline move that could reshape both teams' futures and impact the 2025 fantasy baseball landscape.

Arizona Diamondbacks pitcher Zac Gallen pitches during the first inning against the Chicago White Sox at Rate Field. | Patrick Gorski-Imagn Images

Arizona Diamondbacks starting pitcher Zac Gallen is in the midst of a down season, but has proven himself to be an ace since entering the league in 2019. Still just 29 years old, there is no reason to believe he's washed up or on the downside of his career. With Gallen in a contract year, he's a likely trade piece for the Diamondbacks if the team decides to be sellers at the deadline. 

The New York Mets are a team that is in need of starting pitching. Kodai Senga, Sean Manaea, and Frankie Montas have all been dealing with injury issues and have durability concerns, so adding additional pitching makes sense for the Mets. Gallen could be a nice addition to bolster their rotation. While the Mets aren’t typically known for revitalizing struggling players, they have to make moves and take calculated risks—bringing in someone they hope can spark a turnaround and help them finally make a deep playoff run.

New York Mets - Arizona Diamondbacks Mock Trade

New York Mets Receive

RHP - Zac Gallen

Arizona Diamondbacks Receive

INF - Luisangel Acuna

Prospect - RHP Nate Dohm

Why The Trade Makes Sense For The Mets

It's going to be an important trade deadline for the Mets, who have been winning with a lot of smoke and mirrors. Their pitching overperformed early, their lineup is solid at the top but very mediocre beyond the top four, and they aren't a particularly strong team in the field. They need to add difference makers if they plan to compete with the more talented teams in the National League, like the Los Angeles Dodgers and Philadelphia Phillies. Being that the Mets aren't as good of a team, they need to add high-upside players like Gallen and hope to catch lightning in a bottle if they are going to go on a deep playoff run and knock off superior teams.  

This pitch by Zac Gallen made absolutely no sense 🤯
pic.twitter.com/CxUcMDfMYK

— Kent Murphy (@KentMurphy) July 14, 2025

Why The Trade Makes Sense For The Diamondbacks

As Arizona falls out of contention, it makes sense to move a valuable piece on an expiring contract. Like most selling teams, it's a no-brainer to get something for nothing. They can move off of Gallen, get a solid young player in Acuna, and still have the opportunity to bid on Gallen's services again this offseason if they want to bring him back. Acuna is a player they can build around for the future due to his elite defense and speed, while also getting a flyer on a young pitcher like Dohm.

Fantasy Baseball Impact

As we mentioned earlier, joining the Mets generally doesn't lead to a career resurgence for players, quite the opposite, honestly. Nevertheless, the Mets have to hope that if they add a proven ace like Gallen, he will return to form. This season, he is just 7-10 with a 5.40 ERA and 1.37 WHIP. Those are by far the worst numbers of his career, and it would be tough for things to get much worse for the final few months of the season. Still, if anyone can get the worst out of a player to a shocking degree, it would be the Mets.

That being said, Citi Field is a pitcher-friendly park and Gallen would prove to be an upgrade over Montas at the backend of the rotation. With Griffin Canning and Tylor Megill injured, Gallen would slot in as the club’s No. 5 starter behind Senga, Manaea, Clay Holmes, and David Peterson. That’s a pretty solid pitching staff for a team that lacks a true ace.