Yilber Diaz Stats & Scouting Report

IP	28.1
ERA	3.81
WHIP	1.38
BB/9	3.81
SO/9	6.04

Full name Yilber Daniel Diaz
Born 08/19/2000 in Guatire, Venezuela
Profile Ht.: 6'0" / Wt.: 190 / Bats: R / Throws: R

Top Rankings

Organization Prospect Rankings

BA Grade/Risk: 50/Medium.

Track Record: Diaz’s frustration over going unsigned as a teenager in Venezuela prompted him to quit baseball and travel South America. He spent time in Colombia and Peru, working odd jobs and occasionally panhandling before being lured back to baseball. The Diamondbacks spotted Diaz in late 2019 throwing in the low 90s. In March 2020, they brought him to their facility in the Dominican Republic to undergo a physical. He got stranded there due to the pandemic but continued to get better, eventually signing in February 2021 for $10,000. He has shown steady improvement ever since, making his big league debut in 2024 and pitching well both as a starter and out of the bullpen.

Scouting Report: Diaz has electric stuff, starting with a 94-98 mph fastball that sits 96 with enough carry that it works at the top of the zone. His power curve is his most reliable secondary pitch and a swing-and-miss offering. His slider took big strides in 2024 and was a real weapon in the big leagues, where it elicited a 36.5% whiff rate. Diaz entered the offseason driven to develop a changeup that can be more of a factor. His biggest strides in 2024 came in his strike-throwing. He got to two strikes before throwing two balls 60% of the time in 2023, a number that jumped to 72% in 2024.

The Future: Many were skeptical Diaz could be an effective starter, but with more strikes and a better third pitch, he started to convert doubters. It is still a control-over-command profile, but more strides there and the addition of a changeup would further enhance his chances to stick in the rotation. As always, the fallback of a power-armed reliever raises his floor.

Scouting Grades Fastball: 60 | Curveball: 60 | Slider: 55 | Changeup: 40 | Control: 55
BA Grade: 50/High

Track Record: After going unsigned at 16 out of Venezuela, Diaz quit baseball for a year or so before giving it another try. The D-backs saw him throwing 92 mph and brought him to work out at their facility in the Dominican Republic, where he got stranded due to the coronavirus pandemic. He continued to improve at the D-backs facility and eventually signed for $10,000 as a 20 year old. Diaz broke out in his first full season stateside and reached Double-A in 2023. He showed flashes of potential but went 3-10, 4.82 with an overly high walk rate to amplify lingering questions about his future role.

Scouting Report: Diaz has some of the most electric stuff in the system. His plus-plus fastball ranges from 95-100 mph with solid carry at the top of the strike zone to induce swings and misses. He backs up his heater with a plus, power curveball that gives him another swing-and-miss weapon. He also throws an average slider that flashes higher and a below-average changeup he rarely uses but is being emphasized by player development staff. Diaz has plenty of stuff, but his delivery remains a work in progress and his control is inconsistent.

The Future: Diaz projects to be a hard-throwing reliever. He has a chance to remain a starter if he refines his control and a third pitch.

Scouting Grades Fastball: 70 | Curveball: 60 | Slider: 50 | Changeup: 40 | Control: 45
BA Grade/Risk: 45/Very High

Track Record: Unsigned at 16, Diaz quit baseball for a year or so before giving it one last try. The D-backs saw him hit 92 mph and brought him to the Dominican Republic in early 2020 to work out. The pandemic hit, stranding him there, but he had access to the team's facility, allowing him to eat well and train regularly. Within months, he was up to 95 mph and the D-backs signed the then-20-year-old for $10,000. He enjoyed a breakout 2022 season, reaching High-A and seeing his velocity approach triple-digits.

Scouting Report: At his best, Diaz has a fastball that can sit at 96 and touch 99 mph. The pitch has good carry and he uses it well at the top of the zone. His curveball is his most trusted secondary pitch, but it can get loopy at 76-78 mph. He began throwing a slider last season and it flashed plus with tight, lateral action. It could become his best weapon after his fastball. He also has a changeup that he throws with good selling action. It projects to be an average pitch. Diaz has below-average control that could get to fringe-average in time.

The Future: Diaz has some characteristics that could allow him to develop into a starter, but the club's newfound depth in that area -- and Diaz's subpar command -- could push him into a relief role sooner than later. Scouting Grades: Fastball: 70. Curveball: 50. Slider: 55. Changeup: 50. Control: 45.

Scouting Reports

BA Grade/Risk: 45/Very High

Track Record: Unsigned at 16, Diaz quit baseball for a year or so before giving it one last try. The D-backs saw him hit 92 mph and brought him to the Dominican Republic in early 2020 to work out. The pandemic hit, stranding him there, but he had access to the team's facility, allowing him to eat well and train regularly. Within months, he was up to 95 mph and the D-backs signed the then-20-year-old for $10,000. He enjoyed a breakout 2022 season, reaching High-A and seeing his velocity approach triple-digits.

Scouting Report: At his best, Diaz has a fastball that can sit at 96 and touch 99 mph. The pitch has good carry and he uses it well at the top of the zone. His curveball is his most trusted secondary pitch, but it can get loopy at 76-78 mph. He began throwing a slider last season and it flashed plus with tight, lateral action. It could become his best weapon after his fastball. He also has a changeup that he throws with good selling action. It projects to be an average pitch. Diaz has below-average control that could get to fringe-average in time.

The Future: Diaz has some characteristics that could allow him to develop into a starter, but the club's newfound depth in that area -- and Diaz's subpar command -- could push him into a relief role sooner than later. Scouting Grades: Fastball: 70. Curveball: 50. Slider: 55. Changeup: 50. Control: 45.
BA Grade/Risk: 45/Very High

Track Record: Unsigned at 16, Diaz quit baseball for a year or so before giving it one last try. The D-backs saw him hit 92 mph and brought him to the Dominican Republic in early 2020 to work out. The pandemic hit, stranding him there, but he had access to the team's facility, allowing him to eat well and train regularly. Within months, he was up to 95 mph and the D-backs signed the then-20-year-old for $10,000. He enjoyed a breakout 2022 season, reaching High-A and seeing his velocity approach triple-digits.

Scouting Report: At his best, Diaz has a fastball that can sit at 96 and touch 99 mph. The pitch has good carry and he uses it well at the top of the zone. His curveball is his most trusted secondary pitch, but it can get loopy at 76-78 mph. He began throwing a slider last season and it flashed plus with tight, lateral action. It could become his best weapon after his fastball. He also has a changeup that he throws with good selling action. It projects to be an average pitch. Diaz has below-average control that could get to fringe-average in time.

The Future: Diaz has some characteristics that could allow him to develop into a starter, but the club's newfound depth in that area -- and Diaz's subpar command -- could push him into a relief role sooner than later. Scouting Grades: Fastball: 70. Curveball: 50. Slider: 55. Changeup: 50. Control: 45.