Cardinals Should Bet on Zac Gallen This Winter, Despite 6.12 ERA Slump

The St. Louis Cardinals should be all over the Arizona Diamondbacks hurler this winter.

Sep 9, 2026; Kansas City, Missouri, USA; Arizona Diamondbacks starting pitcher Zac Gallen (23) throws a pitch in the first inning against the Kansas City Royals at Kauffman Stadium. Mandatory Credit: Peter Aiken-Imagn Images | IMAGN IMAGES via Reuters Connect

When the 2026 Major League Baseball season comes to a close, the St. Louis Cardinals need to get to work and look around at the potential options around the league who could help take this starting rotation to another level in 2026.

Progress was made in 2026. That much is true. The Cardinals' rotation had the 25th-best staff ERA in 2025 at 4.67. With just a few days left to go in the season, the Cardinals' rotation currently has the 11th-best staff ERA at 4.10. Still, this is a club that could use another veteran hurler towards the top of the rotation. Kyle Leahy, Michael McGreevy and Andre Pallante should all be in the rotation next year. Quinn Mathews should be in the mix for a spot as well. But the Cardinals need another veteran who has been around the block, in large part because this is a young rotation we're talking about with even more young pieces towards the top of the minors close to the big leagues.

The guy the Cardinals should be circling this winter is Zac Gallen of the Arizona Diamondbacks.

The Cardinals Should Bet On Zac Gallen

Arizona Diamondbacks right-hander Zac Gallen (23) pitches against the San Francisco Giants at Chase Field in Phoenix on July 1, 2026. | USA TODAY Network via Reuters Connect

Gallen is 31 years old and has eight years of big league experience under his belt. He's a former All-Star with a 3.82 career ERA in 197 big league appearances. He's going to be one of the most intriguing starters in free agency this winter. There's no denying the talent, but he has had a difficult season, to say the least. Gallen has a 6.12 ERA in 21 appearances. It has been the most difficult season of Gallen's career to this point. Gallen was offered the qualifying offer after the 2025 season ended, but he declined it.

After looking around, Gallen ended up signing back with the Diamondbacks in mid-February, right around the time Spring Training kicked off. We've seen plenty of examples over the years of guys struggling after signing late. Just a few years ago, old friend Jordan Montgomery had the worst season of his career as a member of the Diamondbacks after signing late before the 2024 season.

In Gallen's career, seven seasons have been very solid and one has been bad. That sounds like someone to bet on a bounce-back. With him coming off a tough season, Gallen would be an intriguing player to target, like Dustin May. Hand him a one-year prove-it deal with an option and see if he can turn things around. With May, things worked out. He was solid and then was traded in a deal for two good prospects. Gallen is a guy who has been better throughout his career and would take the Cardinals' rotation to an even higher level. Then, if things didn't work out in the standings, look for a trade next summer.

The Cardinals need a veteran presence in the rotation to put around these young guys. Gallen would be that and wouldn't break the bank. The second free agency opens, he should be St. Louis' top target.