MLB Mock Trade: Arizona Diamondbacks Deal Zac Gallen To Toronto Blue Jays

Could the Blue Jays add a former All-Star starting pitcher to help bolster their rotation for the pennant race?

Arizona Diamondbacks right-hander Zac Gallen (23) warms up before pitching against the Houston Astros at Chase Field on July 21, 2025. | Joe Rondone/The Republic / USA TODAY NETWORK via Imagn Images

The Toronto Blue Jays have surprised many so far this season, currently holding a four-game lead over the Yankees for first place in the AL East. They have done this, however, with a bottom-ten 4.09 Team ERA.

As currently constructed, the Blue Jays would head into the postseason with a rotation of Kevin Gausman, Chris Bassitt, José Berríos, Max Scherzer, and Eric Lauer. While that group isn’t without promise, there are legitimate concerns at the back end. Future Hall of Famer Max Scherzer, who turns 41 on July 27, has struggled to stay healthy, logging just five starts this season with a 4.70 ERA over 23 innings. Lauer, meanwhile, has been a pleasant surprise — posting a 5-2 record with a 2.80 ERA across 61 innings after a bounce-back stint in the KBO following a rough 2023 campaign with Milwaukee. However, questions remain about the sustainability of his performance, which could prompt Toronto to explore additional pitching help.

One potential target is Zac Gallen, who is enduring a career-worst season. He owns a 7-11 record and a 5.58 ERA through 121 innings while surrendering an MLB-high 23 home runs. A change of scenery could rejuvenate the former All-Star before he hits free agency after the 2025 season.

Blue Jays Interested In Zac Gallen https://t.co/zqhpRuxhIY pic.twitter.com/uCqmhc3b5D

— MLB Trade Rumors (@mlbtraderumors) July 13, 2025

So what would it take for the Jays to acquire D-backs Struggling Ace Zac Gallen?

Arizona Diamondbacks - Toronto Blue Jays MLB Mock Trade

Toronto Blue Jays Receive 

 RHP Zac Gallen

 Arizona Diamondbacks Receive

Blue Jays #14 prospect LHP Adam Macko

Blue Jays #29 prospect OF Victor Arias

In this proposed trade, the Diamondbacks receive a promising left-handed pitcher currently in Triple-A and a contact-oriented outfielder making strides in Double-A. Adam Macko has struggled this season, posting an 8.28 ERA over 25 innings, but his mid-90s fastball and sharp curveball provide reasons for optimism that he can develop into a valuable asset. Meanwhile, Gabriel Arias has performed well at the plate, slashing .287/.380/.426 with five home runs and 36 RBIs over 69 games between High-A and Double-A.

Fantasy Baseball Impact:

Gallen's fantasy value could see a modest boost with a move from the fourth-place Diamondbacks to the first-place Blue Jays, potentially improving his 7-11 win-loss record. The ballpark shift—from the slightly pitcher-friendly Chase Field to the more neutral Rogers Centre—should have minimal impact, especially given that Gallen has already surrendered a league-high number of home runs. Overall, a change of scenery should work in Gallen’s favor moving forward.