Mariners Draft Profile: Funky Florida State lefty Jamie Arnold

On Seattle Sports’ Brock and Salk this week, they’re letting producer Lyle Goldstein take the reins for a daily Seattle Mariners draft profile segment.

Previous M’s Draft Profile: Oregon State – and ex-UW – SS Aiva Arquette

Goldstein is also half of the Marine Layer podcast that covers the Mariners closely, and he’s had his eye on this MLB Draft for a while, especially since the M’s were lucky in the draft lottery and landed the No. 3 overall pick.

The draft starts with the first round at 3 p.m. Sunday on ESPN and MLB Network. Here’s Goldstein’s second profile, which focuses on Florida State left-handed pitcher Jamie Arnold.

Seattle Mariners Draft Candidate: Jamie Arnold

Pros

• Until a couple months ago, Arnold was projected to be the No. 1 overall pick. If it all works out to the absolute 100th percentile, he could be a 6-foot-1, 188-pound version Chris Sale: a crafty lefty with an extremely unique and unorthodox delivery. He poses a real challenge for opposing bats from a three-quarter arm slot.

• Arnold has a four-pitch mix of a fastball, sweeper, changeup and cutter. His fastball has gotten up as high as high as 97 mph and sits in the mid-90s, and he throws his sweeper for a lot of strikes. That pitch had a very high 41% whiff rate in 2024, and he can really command to the back foot of right-handed hitters.

• Arnold has had back-to-back seasons of exactly a 2.98 ERA at Florida State. In 2024, he punched out 159 batters in 105 2/3 innings for a powerhouse baseball school.

• He has pitched in big games and lived up to the moment, including six innings of one-run ball with nine punchouts in a super regional at Oregon State.

Cons

• The concerns with Arnold are led by the swing and miss rate on his fastball, which took a decent jump down in 2025 and is a bit of a red flag. It forced him to rely on his secondary pitches a lot more than desired.

• Additionally, when you throw the way he does paired with his frame, which is not big, there will always be injury concerns. And that’s where you find the flip side in Arnold’s comparison to Chris Sale, who even with a much bigger 6-6 frame still has had Tommy John surgery in his career.

• There is also the element of his mechanics and delivery being so unorthodox that he would be a tough guy to properly evaluate and develop. The Mariners have had a lot of success drafting right-handed college arms with fastball-slider combos and (usually) pretty clean and repeatable deliveries, but this regime has never had a pitcher with this model of a really unique lefty with unusual mechanics.

JAMIE ARNOLD IMMACULATE INNING 🤯🔥 @FSUBaseball pic.twitter.com/92dhSOq7n8

— ACC Network (@accnetwork) June 2, 2024

The verdict

Arnold would be a high-risk, potentially high-reward candidate with the No. 3 pick. The highest of high outcomes is Chris Sale, but there is a profile here where if he doesn’t develop as expected (paired with potential injury risk), he could end up being a reliever or a No. 5 starter.

Either way, he will likely take some time to develop. It’s unlikely that he will fly to the big leagues in a short time span like some of the other college left-handers towards the top of this draft class have the chance to do.

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