Early in the Arizona Diamondbacks’ history, thoroughly dominating pitching became the trademark of the club, never more so than in their march through the 2001 Postseason and World Series title.
Randy Johnson and Curt Schilling combined that year to both post Cy Young-caliber seasons, and won Co-MVP of the World Series. They followed that up with an equally-impressive regular season in 2002, both again putting up Cy Young-level seasons.
While it was Johnson that took home the hardware four straight seasons from 1999-2002, cementing himself as the greatest Diamondback of all time, Schilling was clearly 1A next to Johnson.
Brandon Webb joined the big league club in 2003, and was arguably robbed of a Rookie of the Year award that year. He went on to become the best pitcher in the National League for a four-season run that included a 2006 Cy Young Award, finishing second in 2007 and 2008.
Webb’s career was cut short by a shoulder injury, but his accomplishments over six years stand out as statistically the most valuable of anyone’s other than Johnson’s.
There is no question that Johnson, Schilling, and Webb form the first three of the Diamondbacks pitching “Mount Rushmore.” There is room up on that mountain for one more, however.
Zac Gallen’s History with the Diamondbacks
Sep 15, 2025; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen (23) pitches against the San Francisco Giants during the first inning at Chase Field. Mandatory Credit: Joe Camporeale-Imagn Images | Joe Camporeale-Imagn Images
Gallen was brought over to the Diamondbacks from the Miami Marlins at the 2019 trade deadline in exchange for the club’s number one prospect, Jazz Chisholm. In eight starts that year for Arizona he posted a 2.89 ERA, immediately showing he was a pitcher to be reckoned with.
He followed that up with a 2.75 ERA in the pandemic season of 2020 (12 starts, 72 innings). 2021 was an injury-marred season. A hairline fracture in his forearm suffered during batting practice disrupted his spring training and delayed his season debut to April 13.
Two more IL stints followed, due to a sprained elbow in May and hamstring in July. That all resulted in a 4-10 record and 4.30 ERA in 23 starts.
Gallen then went on a three-year run as one of the best pitchers in all of MLB. From 2022-2024 he made 93 starts, threw 542 innings, and went 43-19 while posting a 3.20 ERA, 131 ERA+. Gallen was the starter for the National League in the 2023 All-Star game.
The 2022 season was punctuated by a franchise-record 44.1 scoreless inning streak. His 12.3 WAR for the three-year span ranked 4th best in MLB during that time.
While 2025 was a down year for Gallen, in which he posted a 4.83 ERA, he was much better over the final two months of the season, heading into his walk year. Now a free agent, he is expected to reject his qualifying offer and end up signing elsewhere. His Diamondback career is almost certainly over.
Why Zac Gallen belongs on Diamondbacks Pitching Mount Rushmore
The chart below shows the top 10 starting pitchers in franchise history. The table is sorted by aWAR (the average of Baseball-Reference and FanGraphs WAR). But park- and league-adjusted metrics such as ERA- and ERA+, along with traditional metrics such as ERA, WHIP, W-L are shown as well.
Diamondbacks Top Starting Pitchers Franchise History | Jack Sommers
There are two other pitchers in franchise history that could potentially challenge for that spot, but both fell short in this writer’s opinion.
Merrill Kelly has been excellent for the Diamondbacks, in fact better than Gallen over the last year or two. While a close second, Kelly has never quite reached the heights that Gallen did.
Zack Greinke matched and even exceeded Gallen on a rate basis (ERA, ERA-, ERA+, etc). But his volume is lower due to being traded.
Had he been able to finish his contract with Arizona, he likely would have matched Gallen in WAR, and his rate advantage would have shrank or disappeared. Greinke posted 3.4 WAR with Houston after the trade but just a 113 ERA+, 3.89 ERA.
A twitter poll shows a plurality of fans agree with the choice of Gallen, although some recency bias due to his poor 2025 clearly cost him votes.
Make sure to see table in first reply before voting
RJ, Webb, & Schilling clearly on D-backs SP Mount Rushmore. Only room for 1 more. Using objective performance measures, Gallen, Kelly, and Greinke are 3 candidates
Zac more WAR, Zack better rates, MK better postseason
— Jack Sommers (@shoewizard59) November 14, 2025SUMMARY
Gallen was also a model representative of the organization both in the clubhouse and in the community (and with the media, too). Always professional, willing to speak through whatever ups and downs he had, and never a whiff of controversy or trouble.
He frequently displayed a good sense of humor too, willing to laugh along with and even at himself at times.
He enjoyed interacting with fans and was always a quick and willing participant to engage and sign at appropriate times.
Don’t allow recency bias to creep in when it comes time to evaluating Zac Gallen’s career as a Diamondback. He was a legitimate ace of the staff, and for a time, one of the best pitchers in MLB. He belong on the Diamondbacks Mount Rushmore of pitchers.
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