Rockies Pitching Prospect Thriving Despite Unorthodox Stuff and Pitch Mix

A Colorado Rockies pitching prospect is thriving despite not having elite stuff.

Feb 20, 2025; Scottsdale, AZ, USA; Colorado Rockies pitcher Sean Sullivan (85) as shot during MLB Media Day at Salt River Fields. / Allan Henry-Imagn Images

One of the biggest weaknesses for the Colorado Rockies year in and year out is the performance of their pitching staff.

Sometimes, it isn’t a lack of talent on the roster; the conditions of pitching at Coors Field are brutal in the altitude, with baseballs flying around the yard.

The Rockies are certainly hoping that top prospect Chase Dollander, a first-round pick in the 2023 MLB draft, can pan out after what has been a difficult start to his professional career in 2025.

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However, it will take more than one pitcher for Colorado to get back on track, as they need plenty of help on the mound.

Right now, their farm system is lacking any impact pitchers, with the highest rated prospect being right-hand pitcher Brody Brecht.

However, there is another pitcher who is starting to garner some attention with an unorthodox style, leading to success.

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Sean Sullivan, a second-round pick the same year as Dollander out of Wake Forest, is a left-handed pitcher who isn’t going to blow away opponents with a high velocity arsenal but is finding a lot of success.

“Advanced command, a quality changeup and deceptive mechanics could make him the rare MLB starter without a plus fastball,” wrote Joel Reuter of Bleacher Report in a recent piece ranking the farm systems of every franchise in the MLB.

He has performed incredibly well in the minor leagues with a 2.17 ERA across his first 165.2 innings with 188 strikeouts. 

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His control is impeccable, with only 23 walks issued and he does a wonderful job of limiting hard contact, surrendering just 13 home runs.

That pinpoint control is imperative for Sullivan, whose fastball doesn’t reach 90 mph on average.

In this day and age, velocity and stuff are normally king when it comes to performing on the mound, but the crafty lefty is finding a way to succeed despite unorthodox stuff and pitch mixing, with a promotion to Triple-A potentially being in the near future.

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