A strong starter for the Wake Forest Deamon Deacons behind Rhett Lowder—whom many had linked to the Rockies prior to the draft—Sullivan is a big bodied lefty with a three pitch mix. His primary pitch is a high-spin four seam fastball that sits in the low 90s that he threw 75% of the time this season. Even though batters expect the pitch, he uses a low release point to create movement in the strike zone. The pitch carried a 36% whiff rate in 2023 as Sullivan had the second best K/9 in the NCAA at 14.3, as well as one of the best WHIPs and opponent batting averages among all Division I pitchers.
What a debut for Northwestern transfer Sean Sullivan, who punched out 10 in just four scoreless innings. High spin fastball up to 2633 rpms from that slot . I lost track of whiffs he got on the heater. 10+ He's gonna to play a huge role for the Deacs. pic.twitter.com/bFbUXRQX8v— Burke Granger (@burkegranger) February 19, 2023
Sullivan also throws a slider that sits mid-to-upper 70s and a changeup as his breaking pitches. He has a quick and repeatable—if unconventional—delivery.
Sullivan made 10 starts through 17 appearances for the Demon Deacons after transferring from Northwestern. He posted a 2.45 ERA in 2023 with 111 strikeouts to just 21 walks in 69 2⁄3 innings.