6 SF Giants prospects who could make an impact this season: 5. Sean Hjelle
On the opposite end of the pitching prospect spectrum from Doval, Sean Hjelle does not have premium velocity. He might not have a pitch in his arsenal that earns plus grades but could be exactly the innings-eater the Giants need if their rotation continues to be hit by injuries. While he is not currently on the 40-man roster, he will become eligible for the Rule 5 draft this winter, almost assuredly requiring he be added this offseason.
Drafted by the Giants in the second round of the 2018 MLB draft, Hjelle has remained a mid-tier prospect for the entirety of his professional career. Ranked the 13th-best prospect in the farm system heading into the season, Hjelle picked up right where he left off in 2019 at Double-A. In 14 starts for the Richmond Flying Squirrels, before he was promoted to Triple-A, Hjelle recorded a 3.15 ERA across 65.2 innings with 69 strikeouts and 19 walks.
Hjelle has flashed for average or better big-league pitches over his career, but his curveball has clearly emerged as his best pitch. His fastball plays up early in his outings, when it sits in the mid-90s, but does tend to dip as he tries to work the second time through the order. However, while Hjelle may not have an overpowering arsenal, at nearly seven feet tall, he generates fantastic groundball rates from his unique approach angle.
Sacramento has been a tough adjustment for Hjelle, as it is for nearly every pitcher. While he’s completed 12.1 innings in two starts, he’s issued twice as many walks (6) as strikeouts (3). Given his development path, Hjelle probably needs some significant time at Triple-A before he’ll be ready to pitch in the majors. However, with limited starting pitching depth in the upper minors, Sean Hjelle might need to be called upon (even for just a start or two) sooner than anticipated.