Young Diamondbacks Pitcher Claimed by the Tigers

This former Diamondback won't be staying in the organization.

Jul 28, 2024; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Yilber Diaz (45) pitches against the Pittsburgh Pirates during the first inning at Chase Field. Mandatory Credit: Joe Camporeale-Imagn Images | Joe Camporeale-Imagn Images

One of the Arizona Diamondbacks' more intriguing pitching prospects will be moving on to a different organization.

According to a new report from AZCentral's Nick Piecoro, right-handed flamethrower Yilber Diaz, who was designated for assignment earlier this week, has been claimed off waivers by the Detroit Tigers. As a result, Diaz's journey through the Diamondbacks' organization will come to an end.

Diamondbacks' Yilber Diaz claimed by Tigers

Arizona Diamondbacks pitcher Yilber Diaz during spring training practice at Salt River Fields at Talking Stick in Scottsdale on Feb. 13, 2025. | Rob Schumacher/The Republic / USA TODAY NETWORK via Imagn Images

Diaz, 25, was ranked as the No. 22 prospect in Arizona's system this season, and has hung around their top 30 prospect rankings for some time. Though he's appeared in major league contests in three separate seasons from 2024-2026, he never accrued enough time to graduate from prospect status.

Diaz is a hard thrower with a strong fastball, but his command has always been somewhat of an issue. He took a step back in 2025, and had to spend some time in the lower ranks of Arizona's farm system while working on improving said command.

He'd been putting forward positive results for the Triple-A Reno Aces this season, with a 4.50 ERA that is considered well above average in the hitter-friendly Pacific Coast League environment. He struck out 43 batters in 32 Triple-A innings this season, which was good for a stellar 12.09 K/9, but he also issued nearly six walks per nine innings, with 21 free passes in 2026.

In the majors, he has a career ERA of 6.19 in just nine career appearances (32 innings). He was initially a starting pitcher, and made a handful of successful spot-starts with the Diamondbacks in the 2024 season, but has since converted to a relief role.

Unfortunately for both he and Arizona, that conversion did not lead to more MLB success. He was called up on June 19 following the news that right-hander Ryne Nelson would miss time with an elbow injury.

He only managed to record two outs in his lone appearance of this season, however, giving up an astonishing seven runs in 0.2 innings during a 16-8 blowout at the hands of the Minnesota Twins. The Diamondbacks opted to designate him for assignment just two days later.

Considering Diaz has an upper-90s fastball and has been a standout in the minor leagues at times, it comes as little surprise to see him picked up by another club. It was a long shot a 25-year-old with quality stuff could remain in the D-backs' organization, even with his walk problem.

It's not necessarily a devastating blow to Arizona, which has already sustained quite a bit of attrition in the pitching department, but there is always a need for solid depth on the mound, and Diaz was not without serious potential, if he could find more consistent command.