Jhonathan Díaz is a Venezuelan left-handed pitcher who has been part of the MLB landscape since his debut on September 17, 2021. Born in Valencia on September 13, 1996, the 29-year-old southpaw has been working to carve out a permanent spot in the Seattle Mariners rotation.
Quick Facts
- Full name: Jhonathan Díaz
- Position: Pitcher
- Team: Seattle Mariners
- Number: 74
- Bats / Throws: Left / Left
- Height / Weight: 6’0″ / 170 lb
- Born: September 13, 1996 (age 29)
- Birthplace: Valencia, Venezuela 🇻🇪
- MLB Debut: September 17, 2021
Background
Díaz grew up in Valencia, Venezuela — a country with deep baseball roots — and his left arm eventually opened the door to professional ball. His path to the majors was a patient one: he debuted at 25, which speaks to the grind and development required to reach the big leagues as a pitcher. Once signed, he worked his way up through the minor-league system before pulling on a Seattle uniform for the first time in September 2021.
Professional Career
Since that debut, Díaz has logged big-league innings without quite finding his footing consistently. In 2023 with the Los Angeles Angels, he posted a 10.29 ERA over 7.0 innings with 4 strikeouts — a tough stretch that showed just how thin the margin for error is at this level. Back in Seattle for 2024, he showed improvement: a 4.66 ERA over 9.2 innings with 8 strikeouts, though he finished 0-1 with a 1.76 WHIP.
Early in 2025, Díaz has flashed real promise — a 0.00 ERA over 1.1 innings with a 0.75 WHIP and 1 strikeout. Small sample, but the right direction.
Career Stats
- 2025 – Seattle Mariners: 0.00 ERA | 0-0 | 1 K | 0.75 WHIP | 1.1 IP
- 2024 – Seattle Mariners: 4.66 ERA | 0-1 | 8 K | 1.76 WHIP | 9.2 IP
- 2023 – Los Angeles Angels: 10.29 ERA | 0-0 | 4 K | 2.86 WHIP | 7.0 IP
Awards and Records
Díaz hasn’t collected individual hardware — no All-Star nods, no Gold Gloves — yet. His career is still in the consolidation phase, with the goal of putting up numbers that put him on that radar.
Worth Knowing
Left-handed pitchers have always been a valued commodity in baseball, and Díaz is part of that minority. His back-and-forth between organizations reflects how competitive roster spots are at the major-league level — even confirmed talent needs the right moment and the right opportunity to truly take off.

