The 1 Thing The Diamondbacks Really Need Zac Gallen to Do vs Rockies

Zac Gallen will need to go deep in Saturday's game to give the bullpen some breathing room

Apr 1, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen against the Detroit Tigers at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | Mark J. Rebilas-Imagn Images

The Arizona Diamondbacks had their five-game winning streak snapped Friday night when they allowed the Colorado Rockies to come back and steal a 3-2 victory.

Arizona will try to get back in the win column Saturday May 23 behind Zac Gallen, who will face off against Rockies' Michael Lorenzen. It's a late 7:10 p.m. MST first pitch. The D-backs have a 26-24 record while the Rockies are 20-32.

But, in particular, the Diamondbacks need one thing from Gallen: a deep outing, as Arizona's bullpen had a rough night on Friday.

Diamondbacks Rockies Starting Pitching Matchup

Apr 18, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen (23) throws against the Toronto Blue Jays in the first inning at Chase Field. Mandatory Credit: Rick Scuteri-Imagn Images | Rick Scuteri-Imagn Images

Michael Lorenzen just faced the D-backs last week in Colorado, and was hit hard, giving up seven runs, six earned, in 4.2 innings. The D-backs won that game 8-6. Lorenzen is 2-6, with a 7.03 ERA. His six losses are the most in MLB.

Looking at the head to head matchups, Corbin Carroll is the biggest threat to the Rockies right-hander. Carroll has two homers against Lorenzen, including one in the game May 17.

Note Lourdes Gurriel Jr. was removed from the table below as he is day to day with a hamstring injury and is getting imaging on Friday morning. News of a roster move is still pending as of this writing.

Current D-back hitters vs Michael Lorenzen | Baseball-Reference

Zac Gallen's most recent start was of the quality variety, going six innings and allowing just two runs to the Giants in a 12-2 D-backs rout. He was pulled after just 81 pitches. It was just the second quality start of the year for Gallen, who has a 2-4 record with a 4.78 ERA.

Gallen did not pitch in the Coors Field series last week. Ezequiel Tovar has been a thorn in Gallen's side in his career so far, going 6-for-13, .462 against him. Gallen faced the Rockies on May 17 last year at Chase Field and gave up six runs in a 14-12 Rockies win.

Current Colorado Rockies vs Zac Gallen stats | Baseball-Reference

Diamondbacks vs Rockies Bullpens

May 10, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Juan Morillo against the New York Mets at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | Mark J. Rebilas-Imagn Images

Manager Torey Lovullo pulled starter Michael Soroka after just 78 pitches Friday, citing pitcher fatigue as the reason. As a result of that ill-fated decision, the Diamondbacks ended up using four relievers in the loss.

Juan Morillo and Ryan Thompson both gave up runs and totaled 58 pitches between them. Along with Taylor Clarke and Brandyn Garcia, D-backs relievers had to throw 77 pitches to record the final nine outs. In addition, Kevin Ginkel and Jonathan Loaisiga both warmed up in the bullpen without getting into the game. Closer Paul Sewald had the night off however.

All this is to say is the D-backs bullpen, which Lovullo spent so much time protecting and trying to let them catch up while the rotation was hot, is suddenly in a tough spot. There are five more games before the next off day May 28. It would not surprise if there were a bullpen roster move Saturday to go along with a Gurriel replacement.

The Rockies only had to use two relievers on Friday, including closer Antonio Senzatela, who used 18 pitches to lock down the save. Co-closer Juan Mejia threw 27 pitches on Thursday while taking the loss in the D-backs walk-off victory. That was his third outing in four days, but he had Friday off.

So there may be some workload issues for the Rockies at the back end of their bullpen as well. Don't be surprised if there are late inning fireworks for either team Saturday.