Looking back on the St. Louis Cardinals’ decision to trade Zac Gallen

The St. Louis Cardinals have traded away promising players to fill holes on the major league roster. How have they fared on other rosters?

I recently reviewed the Cardinals’ trade of Sandy Alcantara to the Marlins, a deal that netted them Marcell Ozuna.  Of course, it wasn’t just Alcantara who was sent to Miami.

Zac Gallen had made just 29 minor-league starts when he was shipped south, though he did reach Triple-A by the end of his first full professional season in 2017.  He spent the entire 2018 campaign with the Marlins’ Triple-A squad, the New Orleans Baby Cakes (what a name!) before getting the call to the big leagues in June of the next year.

Though Gallen made a successful seven starts with Miami, with a 2.72 ERA and 43 strikeouts in 36-1/3 innings, the team had other plans for him than leaving him in their rotation.  At the July 31 trading deadline, the Marlins traded Gallen to the Diamondbacks in return for minor-league middle infield prospect Jazz Chisholm. 

Chisholm was solid in 124 games for the Marlins in 2021 and looks to be a key cog for the team at second base and/or shortstop going forward.  And to circle back around, I covered Ozuna’s Cardinals contributions in my Alcantara article.  Gallen, meanwhile, pretty much duplicated his Miami numbers in Phoenix, posting a 2.89 ERA in 43-2/3 innings with 53 strikeouts over eight starts.

It was more of the same for Gallen in 2020’s shortened season.  He made 12 starts, put up a 2.75 ERA, threw 72 innings, and whiffed 82 batters.  While those ERAs and K rates remained impressively stable in each of those three fractional seasons, Gallen was able to trim his walk rate from 4.5 BB/9 IP with the Marlins to 3.7 after the trade, and then to 3.1 in 2020.   That shortened-season performance was impressive enough to earn him a ninth-place finish in the Cy Young Award voting.

Gallen’s 2021 campaign was the first time he had a bumpy ride in the majors.  A hairline fracture in his forearm delayed his debut until mid-April, an elbow sprain led to another month-plus of games on the injured list beginning in early May, and a hamstring strain put him back on the shelf for two weeks in July.

Those injuries certainly could explain his poor performance in June and July, when he combined to throw 30 innings and cough up 20 earned runs.  While he pitched better both before and after that two-month stretch, Gallen still finished the season with a 4.30 ERA, by a large margin his worst mark as a professional.  However, his 139 strikeouts in 121-1/3 innings and a solid 3.6 walks per nine matched his career rates almost perfectly.

Will Gallen continue to be another strong starting pitcher the Cardinals have traded away?  He’s sure done well so far, and since he’s scheduled to earn the major-league minimum again in 2022 — pending any changes to baseball’s collective bargaining agreement — the Diamondbacks will have no issues leaving him in the starting rotation for the foreseeable future.  The 26-year-old pitcher should be entering the prime of his career.

The Cardinals were looking for a thumper at the end of 2017 when they acquired Ozuna, and they had surplus pitching to deal.  Prospects often don’t work out, but this is a case where both teams that have acquired Gallen have reaped the benefits, and those benefits look like they will continue to accrue for Arizona for a few more seasons.