A look at the Arizona Diamondbacks’ potential Opening Day starting rotation

What could the Arizona Diamondbacks' starting rotation look like at the start of next season?
Arizona Diamondbacks Zac Gallen (23) pitches against the Pittsburgh Pirates at Chase Field in
Arizona Diamondbacks Zac Gallen (23) pitches against the Pittsburgh Pirates at Chase Field in / Joe Rondone/The Republic / USA TODAY
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Zac Gallen
World Series - Texas Rangers v Arizona Diamondbacks - Game Five / Christian Petersen/GettyImages

Zac Gallen

Zac Gallen finished third in National League Cy Young voting and even received a few down-ballot MVP votes. Believe it or not, but 2023 wasn't even the best season of the right-hander's career. That's not to say his campaign was bad, but he could definitely build upon his '23 season and be even better next year.

Gallen pitched 210 innings, working to a 3.47 ERA, 3.26 FIP, and 1.12 WHIP. Gallen struck out 26% of the batters he faced and only had a walk rate of 5.6%. His 0.94 HR/9 rate was also above average. Last season, Gallen was one of only five pitchers to have thrown at least 200+ innings. He was tied with Gerrit Cole among those five arms for the most fWAR at +5.2.

Gallen's season was great, but two factors were slightly worrying: his ability (or inability) to prevent hard contact. Batters owned a 91.5 MPH exit velocity and a 46.2% hard-hit rate against him, both of which were in the 5th percentile or worse. His 9.2% barrel rate was also one of the lowest in baseball. In 2022, he had an 87.8 MPH exit velocity, a 7.8% barrel rate, and a 36.1% hard-hit rate, in comparison.

Gallen's numbers after the All-Star break were good but not great. He only pitched to a 4.03 ERA, 3.94 FIP, and 1.21 WHIP from July 15th onward. Sure, these aren't bad numbers, but the home runs started to catch up to him, and he had a 1.28 HR/9 down the stretch. These struggles carried into the Postseason, as Gallen would allow 17 earned runs on six home runs, 14 walks, and 31 hits in only 33.2 innings.

Still, Gallen could definitely rebound and pitch like he did in 2022 and in the first half of 2023. The right-hander will definitely enter the 2024 season as a Cy Young candidate, as he's now finished top five in voting two years in a row. It will be fun to see what Gallen brings to the table next season atop the Diamondbacks' rotation.