Gallen's Evolution Into An Ace Gives D-backs Huge Trade Win

Arizona paid a high price to acquire Gallen, but his development into one of the game's best pitchers was worth it.

At the 2019 trade deadline, the Arizona Diamondbacks made a trade that sent shockwaves throughout the baseball world. Arizona traded one of their top prospects, infielder Jazz Chisholm Jr., to the Miami Marlins for starting pitcher Zac Gallen. At the time, Gallen was not considered a Top 100 prospect but was a capable starter that was controllable through the 2025 season. 

As we look back on that deal nearly four years later, this deal could not have turned out any better for the D-backs. It's difficult to truly compare the value of a pitcher to the value of a hitter, but there is one stat that does the best job: Wins Above Replacement, or WAR. The edge goes to the D-backs ace at nearly a 3-to-1 ratio, with Gallen posting 12.8 WAR since the trade vs. 4.8 for Chisholm. The head-to-head matchup has also gone overwhelmingly in the D-backs favor, with Chisholm going 0-for-9 with three strikeouts against Gallen.

While they traded a potential superstar talent in Chisholm, Gallen's development into one of baseball's best pitchers was easily worth the price. When asked what has stood out in Gallen's evolution over the past five seasons, here's what his manager, Torey Lovullo, had to say. "Focusing in on the evolution, it's the improvements he makes every start. He's never sitting still. At times when he is studying and preparing a game plan it looks he's playing checkers and everybody else is playing chess. Sometimes I'll watch a game plan unfold and it's totally different than the start before." 

What makes Gallen especially tough for opposing batters is his ability to command four plus quality pitches to any batter on any count. "He has so many weapons that he's gotten better at using at every single start, which has allowed him to attack holes," said Lovullo. "He's never the same guy, he's got a different version of himself every five days and that's impressive. Most guys who get on a run, they stay with what they know until they get banged around. He never lets it get that far, he's going to switch up his game plan every single time. He can do it, because he got the weapons."

Another key element in Gallen's game is his ability to quickly make adjustments during the middle of his starts. That was the case last night, in which Gallen didn't have a great feel for his secondary pitches but made it work with great fastball command.

"I think the skill I learned at a young age was being able to make the adjustment in the least amount of pitches," said Gallen. "With that coupled with being able to look in the mirror and understand what is working that day and how we have to be able to figure it out and still keep it in the game plan but not get burned by it. The older I've gotten, the more I've understood these pitches are really good. I still have to use them, I try not shy away from them. I think that's a maturity thing, just understood maybe that day you might not have it but still got to use it. The biggest thing you don't want to do is let the hitters eliminate a pitch."

Another big reason the D-backs have gotten off to a 20-15 start has been Gallen's ability to rise to the occasion. One of the understated responsibilities of an ace is to play the role of "Stopper", in which he stops his own team's losing streak or the opposing team's momentum. In six starts following a loss, Gallen is 5-0 with a 2.13 ERA. In all six starts, he left the game with the lead. 

Even though the D-backs paid a high price in able to pick up Gallen four years ago, his development into an ace ultimately proved to be worth it.