Diamondbacks' Left-hand Pitching Depth Takes Another Hit

Arizona Diamondbacks left-hander Spencer Giesting was placed on the minor league 7-day Injured List by the Reno Aces with an oblique injury. He will likely miss a month or more of action, according to a Diamondbacks official.

Giesting, 24, was in the middle of a role change, transitioning from a starting pitcher to a reliever with multi-inning capability.

The D-backs' left-handed relief pitching depth, which was already quite thin, will take another hit.

Diamondbacks' Spencer Giesting suffers oblique injury

Feb 18, 2026; Scottsdale, AZ, USA; Arizona Diamondbacks pitcher Spencer Giesting (70) poses for a photo for MLB media day at Salt River Fields at Talking Stick. Mandatory Credit: Allan Henry-Imagn Images | Allan Henry-Imagn Images

Giesting took a step forward in his development during the 2025 season, pitching to an impressive 3.67 ERA in the relatively offense-heavy Texas League as a member of the Double-A Amarillo Sod Poodles.

That earned him a jump to the Triple-A level mid-season, which did not go well at first. In the brutal environment that is the Pacific Coast League, Giesting held an ugly 9.77 ERA through his first nine starts.

But then, something began to click for the southpaw. He delivered a six-inning quality starts three times in the month of August, then pitched to a 3.38 ERA in September to close out the 2025 season. He appeared to be on an upward path.

Giesting made seven appearances in the Cactus League this year — all in relief. He had a handful of poor outings, but also made four scoreless appearances. He made one appearance (in relief) for the Aces to open the 2026 Triple-A season, giving up one run in three innings.

While it did not appear that Giesting was on the fast track to the major leagues anytime soon, the injury does chip away at an area in which the D-backs depth has already been a bit thinned out.

Diamondbacks' left-handed pitching depth is thin

Arizona does not have a left-handed reliever on its major league roster. Eduardo Rodriguez is the only southpaw pitcher.

Left-handers Brandyn Garcia and Philip Abner both appeared to be candidates to make the major league roster, but Garcia struggled to throw strikes consistently, and Abner has been tasked with working on his ability to face right-handed pitching.

Garcia has allowed one run over his first 3.1 innings in Triple-A this season, while Abner allowed three runs (two earned) over 0.2 innings.

Mitch Bratt and Kohl Drake — both starting pitchers — have had some early success this season, but both of those left-handers looked a bit over their heads facing major league hitters during spring training, and could use some more development time in the minor leagues.

Additionally, the organization is likely hesitant to move too quickly in converting either of them to relief, as starting pitcher depth is thinned out as well due to the injury to righty Cristian Mena (shoulder, 60-day IL).