Diamondbacks prospect Jaitoine Kelly becomes youngest World Baseball Classic starting pitcher

Jaitoine Kelly is an 18-year-old pitching prospect for the Arizona Diamondbacks with one game of minor league experience, and on Saturday, he made World Baseball Classic history.

The right-hander from Aruba became the youngest starting pitcher in WBC history, according to MLB researcher Sarah Langs.

At 18 years and 251 days tomorrow, Jaitoine Kelly will be the youngest pitcher in WBC history to start a game

Previous youngest, and only other under age 19: Shairon Martis, also for the Netherlands, on 3/10/06, when he did not allow a hit in a mercy-rule shortened game

— Sarah Langs (@SlangsOnSports) March 6, 2026

The teenager started for Team Netherlands, managed by Hall of Fame inductee Andruw Jones, against Nicaragua, managed by Dusty Baker, in Miami.

And it went well, as Kelly threw two scoreless innings with one hit and three strikeouts while sitting mid-90s mph with his heater.

“For sure more pride, I’m going to represent my country, my island and it’s going to be a great experience for my first time,” Kelly told reporters on Friday.

Kelly is one of three Diamondbacks prospects playing for the Netherlands, along with outfielders Druw Jones and Jakey Josepha.

Kelly signed with the Diamondbacks in January 2024, and he has 20 professional games under his belt, mostly in the Dominican Summer League. He made his debut with Single-A Visalia in September.

The 6-foot-4 hurler is Arizona’s No. 27 prospect on Baseball America:

Kelly has a long way to go but has significant upside given his arm and frame. If it all comes together, he has the potential to be a mid-rotation starter.

Kelly pitched against a Nicaragua lineup headlined by New York Mets infielder Mark Vientos, whom Kelly got to pop out. The opposing pitcher, Erasmo Ramirez, has 336 major league games of experience.

Nicaragua went from having faced Phillies ace Christopher Sanchez of the Dominican Republic on Friday to a youngster with minimal minor league experience. It is part of the WBC’s charm that players of different experience levels get the opportunity to compete with each other for their countries.

Kelly directly followed his brother, Pittsburgh Pirates prospect Antwone Kelly, who started in the Netherlands’ first game of the WBC on Friday, a 6-2 loss to Venezuela.

“Since we were kids, always our dream to play here,” Kelly said. “I saw him play in 2023. It was really a great experience. I want to follow his steps. It’s pretty beautiful to see my brother play in WBC.”

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