Yilber Diaz's High Octane Arm Profiles for Big Bullpen Role

Diaz slots in at the No. 25 spot on the Diamondbacks Top 30 prospects list entering the 2024 season.

This article is part of a series counting down the Diamondbacks Top 30 prospects entering the 2024 season. These rankings are determined by Michael McDermott, in conjunction with the Inside the Diamondbacks staff.

Summary: Yilber Diaz is a shorter, but well-built right-hander who can touch triple digits with his fastball and has a swing-and-miss curveball. Those two pitches give him the floor of a reliever. Signed for just $10K out of Venezuela in February 2021 at 20, Diaz broke through as a prospect when he put up impressive numbers with Class A Visalia in 2022. When he's locked in, he's been overpowering for the lower minors, but has a tendency to overthrow, causing  his control to disappear at times. With his Rule 5 year coming up next offseason, the team needs to find a long term role for him soon. 

Rank: 25

Age: 23

Height/Weight: 6'0" 190 lbs.

Throws: Right

Tools: Fastball 60, Curveball 60, Slider 50, Changeup 40, Command 40, Overall 40

ETA: 2025

2023 Recap: Diaz began the year where it ended the previous year with High-A Hillsboro. His outings yielded a lot of inconsistency, as his ERA was 5.03 but a strikeout rate of 32.9% still showed some promise. He was then promoted to Double-A Amarillo, in which he allowed six runs in 15 innings and helped Amarillo win a Texas League Championship. Regardless of the results, it was still a positive development that Diaz was able to climb a level closer to the big leagues in 2023.

2024 Expectations: 2024 is a make or break year as a prospect, as he'll be eligible for the Rule 5 Draft next season. With his stuff and proximity to the majors, he's a candidate to get selected. With the need to add him to the 40-man roster to protect a high octane arm, Diaz needs to have the type of season that inspires confidence that he can contribute in the major leagues. It's also possible we see a move to the bullpen in 2024, as a means to get his arm to the big leagues faster. He'll open up the year with Amarillo, one of the toughest places to pitch, but ideally either finishes the year in Reno or Arizona.

Projection: As a stuff over command pitcher, Diaz better profiles for the bullpen long term. His fastball and curveball will play up in the role and he can focus on honing in his two main pitches when he only faces a lineup once. Depending on his ability to hit spots, he could profile for a back of the bullpen role and pitching in big innings. Most likely Diaz gets added to the 40-man roster next winter in order to protect him from the Rule 5 Draft.

Top 30 Diamondbacks Prospects Entering the 2024 Season