Blue Jays pitching prospect making the case for a long look in Spring Training

On Sunday, the Arizona Fall League hosted its annual Fall Stars Game. From the Blue Jays’ system, just one prospect suited up, and he certainly made his opportunity worth it.

Kai Peterson, who was drafted in the 20th round of the 2023 Draft, pitched one inning in relief during the sixth inning, as he entered the game with a 4-1 lead. He went toe to toe with Esmerlyn Valdez, the Pirates 15th-ranked prospect, who popped up on the second pitch.

He then went on to walk the next two batters, before he got the 2024 third overall pick and second best prospect in the Rockies system, Charlie Condon, to ground out into an inning ending double play. He wrapped up one inning of work needing 14 pitches, six of which were strikes.

Blue Jays pitching prospect making the case for a long look in Spring Training

The Sierra Junior College alumni ended up throwing only two of his sliders, which typically sit in the low-80's, but generated no swings. The other 12 pitches he threw were his sinkers, which sat around 91 mph in the Fall Stars Game. The sinker generated five swings, but Peterson never ended up generating a whiff.

Back in 2023, Peterson was the final player to be selected by the Blue Jays in the 2023 MLB Draft. He started 16 games earlier that year, owning a 9-2 record with a 3.86 ERA with 127 strikeouts through 84 innings pitched. The southpaw stands 6’ 1, 180 pounds and possesses above-average strikeout stuff. He was not ranked in MLB.com’s top 250 draft prospects, but could end up being a diamond in the rough and an option for some reps during the Blue Jays Spring Training in 2026.

Over 2024 and 2025, he's logged outings in Vancouver, Dunedin, and Double-A New Hampshire. Over 49.2 innings pitched in 2024, he logged a 4.53 ERA while giving up just one homer. Along the way in 2024, he sported an absurd 16.5 K/9 while throwing a sinker around 80% of the time.

His ERA, which was inflated in 2024 by a massive ten earned run blowup, looked much better in 2025. It lowered itself to a 3.04 spanning 50 innings, while displaying a WHIP of 1.351. In the Arizona Fall League regular season, the Glendale Desert Dogs, which holds the Blue Jays’ prospects, isn't doing so well. They own a 10-15 record, although they are still in striking distance, sitting just a game and a half behind the Solar Sox.

The Blue Jays regime of Ross Atkins and Mark Shapiro haven’t done the best job in the first round of drafts so far, other than Alek Manoah who was dominant for a couple of years before falling off the face of the earth.

That being said, they’ve done a solid job at picking up depth players who grind their way through years of the minor leagues, such as Davis Schneider, Addison Barger, Tyler Heineman, and more. Peterson may be one of the names included in that category in a few years. It starts with a bit of a leash in this upcoming Spring Training.