Sean Sullivan’s Fastball Moves In Mysterious Ways For Rockies


The Rockies have seen little of Sean Sullivan but enough to marvel at the mystery the 21-year-old lefthander creates.

He doesn’t throw particularly hard. Sullivan averaged 92 mph from a low three-quarters arm slot and less than that in his second of two instructional league outings. 

“It’s from an angle and with an approach where hitters think it’s actually lower than it ends up,” Rockies assistant farm director Jesse Stender said. “There’s some funkiness to the delivery.

“The (velocity) plays up because it gets on you quicker. And then the ball, especially the fastball, isn’t where you expect it to be when it gets to the plate.”

Drafted this year in the second round out of Wake Forest, Sullivan made two hitless one-inning appearances in the Arizona Complex League, striking out four with one walk.

In one outing at Low-A Fresno, Sullivan faced six batters in two innings and struck them all out.

He struck out the three batters he faced in his first instructional league appearance and then struck out the first two in his second before getting the third on a foul pop out. 

“He struck out 11 straight batters without giving up a hit or a walk,” said Stender, referring to Sullivan’s Fresno outing and two in instructional league.

“It’s truly remarkable because what you see with your eyes is a softer fastball that everybody just swings at and cannot touch.”

Sullivan also throws a slider and changeup but used them minimally. His changeup is a work in progress, and his slider has some depth and projects to be an average pitch. The hope is those pitches develop and can play off his fastball.

“Basically, he’s carried by the fastball,” Stender said, “and he’s pinpoint with his command. And he lives up in the zone.”

Rockies farm director Chris Forbes said Sullivan’s heater is “like an invisible fastball.”

“At some point, he’s going to get squared up. That’s baseball,” Forbes said. “You just kind of almost want to be in the yard if that happens, just to see what’s going on, see how they’re doing it.”


Skyler Messinger took extremely well to the corner outfield positions where he began working in instructional league. The Rockies introduced him to first base last season at Low-A Fresno, and he made 34 starts at that position and 49 at third base, his original position. Drafted in the 19th round out of Texas in 2022, Messinger hit .258/.364/.475 in 106 games at Fresno with 18 home runs and a California League-leading 78 RBIs.

— Fresno pitching coach Mark Brewer retired, and Arizona Complex League co-pitching coach Dave Burba wasn’t retained. Brewer, 65, was in the Rockies’ organization for nine seasons. He spent seven seasons, including the last four, at the Low-A level. Burba, 57, was a pitching coach in the Rockies’ system for 13 seasons and one of two pitching coaches with the Rockies’ ACL team. The other is Helmis Rodriguez, who joined that club in 2021 after three seasons as a pitching coach in the Dominican Summer League.

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