St. Louis Cardinals 2024 Top 30 Prospects List: #30-21

Pete Hansen - Shriners Children's College Classic
Pete Hansen - Shriners Children's College Classic / Bob Levey/GettyImages
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24. 1B William Sullivan (2023 level: Single-A)

Sullivan is a left-handed slugger the Cardinals drafted out of Troy in the 13th round last year. He showcased some of the best raw power in the entire 2023 class with a 119 mph max exit velocity and 112.3 mph 90th percentile exit velocity. So why did he slip all the way to the 13th round? I would suspect several reasons played a factor, such as playing at a weaker conference, being an older prospect, playing 1st base, and having some whiff concerns. Additionally, Sullivan struggled in a 40-game sample in the New England Collegiate Baseball League, a wood-bat summer ball league the summer prior to his final collegiate season.

2023 would be far and away Sullivan's strongest season in college, though, as he posted a .310/.416/.625 slash line while hitting 17 home runs. In college, Sullivan improved massively from year to year. In 2021, he had just a .681 OPS, but he brought it up to a respectable .832 in 2023, and in his breakout senior season, he got it up to a ridiculous 1.040. Not only did Sullivan reach incredible top-end exit velocities, but he also consistently made hard contact with a 91.3 mph average exit velocity and 44.7% hard-hit rate to show.

On top of hitting the ball hard, Sullivan made great swing decisions despite being aggressive at the dish. Sullivan had an elite 75.2% z-swing% while only chasing 24.5% of pitches. Sullivan could benefit from a more patient approach as he wasn't particularly stellar at optimizing his launch angle. Sullivan made 79.4% z-con and 52.2% o-con, which was his most glaring weakness in college ball. In his short time at Palm Beach, both values increased, giving me a sense of optimism. In Statcast-tracked games last season, Sullivan had an 87.4% zone contact rate while striking out around 20% of the time. I expect his zone contact rate to lower a bit in a larger sample, but I still find this to be an encouraging development.

Sullivan's exit velocities also remained elite in his first taste of pro ball. Sullivan had a 90.6 mph average exit velocity, 107.7 mph 90th exit velocity, and 112.7 mph max exit velocity, all grading out in the top 5% of hitters in Single-A. Sullivan is already one of the Cardinals' best prospects in terms of strictly raw power. The game power hasn't completely materialized yet, as his iso was only .125, and 5 of his 7 hardest-hit balls were hit on the ground. Sullivan had a groundball rate of 54.4% at Palm Beach, and his sprays were also not ideal for power production. I'm curious to see how his game power profiles in a larger sample this year.

Sullivan is a better athlete than you would think, considering his 6'4, 216-pound frame. He got up to 28.8 ft/sec sprint speed last year and generally lived in the 26-28 ft/sec range on competitive runs, which is below average but probably better than expected. Sullivan exclusively played 1B last year for the Cardinals, but if they wanted to experiment with throwing him in left field, he could potentially handle it. He did play some corner outfield in college. Sullivan made an exceptional impression in his first season in pro ball, and I'm eager to see how the data-darling first baseman performs in his first full season of pro ball.