SF Giants' farm director explains Jonah Cox's ascent to big-league promotion
MILWAUKEE - The Giants didn’t invite Jonah Cox to major league spring training like they did Bo Davidson or Parks Harber. He hadn't played higher than High-A when the season started. He has never been considered one of the organization’s top prospects.
But after two months as the best hitter in all of the minors, Cox found himself leapfrogging Triple-A entirely and making his major league debut on Sunday at Coors Field.
"I think if you put him in center field right now in the major leagues, he'd win a Gold Glove if he played every day," senior director of player development Kyle Haines said before Cox’s promotion. "This guy's a Gold Glove center fielder. He's one of the best baserunners in minor league baseball, if not the best. He's hitting .420 and he doesn't strike out. He hits righties, and he hits lefties.
"If somebody who was picked in the first round was doing exactly what he was doing, he'd be in the argument for top-10 prospect in the whole game of baseball."
Cox is the son of former major leaguer Darron Cox, who played 15 games with the 1999 Montreal Expos under Giants legend Felipe Alou. The outfielder was a sixth-round selection by the Oakland A's in the 2023 MLB draft, then was sent to San Francisco in the Ross Stripling trade.
The 24-year-old spent three collegiate seasons at different schools, bouncing from one JUCO (Butler Community College) to another JUCO (Eastern Oklahoma State College) before landing at Oral Roberts. In 2023, Cox carried the Golden Eagles to their first College World Series appearance since 1978, hitting .412/.470/.646 with 11 homers and 68 RBIs over 66 games.
The center fielder's calling cards have long been his speed and defense. He stole 163 bases in the minors on 192 attempts (84.8% success rate), and his 27 steals with Richmond were tied for seventh in the Eastern League.
Cox hadn’t been exceptional at the plate in his first three seasons in the minors. He hit .257 with 10 homers and a .731 OPS last season with High-A Eugene, only 3 percent better than a league-average hitter by weighted runs created plus (wRC+). But in Richmond, he emerged as much more than a speedy defense-first outfielder by tearing up the Eastern League from the jump.
At the time of his promotion, Cox was hitting .400 over 44 games with the Flying Squirrels. That number wasn't just the highest in the Eastern League. It's not just the highest in Double-A. It's the highest in all of the minors.
"There's some visible adjustments with the offense that we've made and have worked on for a long time," Haines said. "I think our hitting department deserves a lot of credit because there's the long-term development models that we apply, and I think some of them are sticking for him. Jonah deserves a lot of credit, too, for gaining confidence and working hard."
Cox wasn't exactly hitting in the offense-friendly Pacific Coast League either. The Eastern League is notorious for suppressing offense, and the league’s average batting average of .244 is the highest since 2021.
"Everyone knows how good he is on the bases because of his speed, and the speed shows up in the outfield," Giants manager Tony Vitello told reporters in Denver on Sunday. "Maybe at times, labeled a ‘defender/runner' but in my experiences with all young players, the more physical you get - he looks great - and the more experience and more at-bats you get, the better you become offensively, and he's really swung the bat well."
For all the production, it’s important to note Cox’s batting average on balls in play. Cox had an absurd .464 BABIP at the time of his promotion, the highest mark in the Eastern League by a healthy margin, an implication that there was a degree of luck involved in Cox's blistering hot start.
San Francisco hasn't made the bold move to promote a prospect straight from Double-A Richmond since Bobby Evans was running the show, when the team promoted infielder Miguel Gomez and pitcher Dan Slania in 2017. Other notable instances include infielder Matt Duffy and reliever Hunter Strickland in 2014, as well as Pablo Sandoval in 2008.
The lingering question with this bold promotion, which came a day after Harrison Bader hit the injured list, is whether the Giants rushed Cox to the majors, risking his development.
Cox wasn't on the fast track to the majors by any means. In 2023, he played 35 games between the Arizona Complex League and Single-A after being drafted. In 2024, Cox played 57 games with Single-A San Jose and High-A Eugene. In 2025, he spent the whole season with High-A Eugene. Now, following 44 games in Double-A with an abnormally high BABIP, Cox is a Giant.
The likely best course of action for his development is to have him play regularly until Bader is ready to return from the injured list. If Cox's glove is as good as advertised, the Giants can trot him out in center field while batting him low in the lineup and hope that his defense and speed can provide instant value.
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