Pittsburgh Pirates Prospects: Three Underrated Breakout Candidates for 2023

Altoona Curve - Sean Sullivan

Jared Jones seems like too obvious of a pick as a breakout candidate for Altoona. So instead, let’s go with Sean Sullivan. Sullivan was the Pirates’ 8th-round pick in 2021. His first extended look could have gone better, but there were plenty of positives that he could build upon next season at Altoona.

Sullivan worked to a 4.68 ERA, 5.47 FIP, and 1.36 WHIP in 75 innings at Greensboro. However, he did have a decent 25.8% strikeout rate and 8.3% walk rate. The right-hander was one of just nine pitchers in the Pirates’ system with 50+ IP and a K:BB ratio over 3.0. Where Sullivan struggled the most was home runs, having a 1.92 HR/9 rate.

But there is some hope he can improve that next season. Sullivan registered a 3.88 xFIP, which is adjusted for HR/FB ratio. His HR/FB ratio came in at 26.7%, which was the fourth highest rate in minor league baseball last season (min 70 IP). Despite allowing nearly two home runs every nine innings on average, Sullivan had a respectable 41.3% ground ball rate and flyball rate under 30%.

Sullivan typically works in the low-90s, but can hit 95-96 MPH. He also throws a plus slider, though his four-seamer, curveball, and change-up are all average pitches at best. He also displays solid command, and while he is a later-round selection, he is still fairly young. Next year will only be his age-22 campaign. He's making decent progress.