Blake Street Banter Team | February 16, 2025

It’s day 3 of BSB Tools Week where our staff ranks the top tools in each scouting category across the organization. Today, we’re diving into the best fastballs among Rockies prospects. The fastball is such an important pitch to navigate at Coors Field with altitude having less of an impact on the movement of a fastball, as we saw with Seth Halvorsen last season.

The five pitchers below–and our honorable mentions–may have a leg up when it comes to finding future success at Coors Field.

On Friday, we kicked off the series by ranking the best command pitchers in the organization, led by the Wizard Sean Sullivan. Saturday, we featured the top secondary pitches in the organization with Chase Dollander and Brody Brecht leading the way.

Honorable Mentions

Relief prospect, Juan Mejia, has a lively upper-90s fastball that is Major League ready, though a lack of command is preventing him from making the list. Newly acquired lefty Luis Peralta would have made the list with his mid-90s deceptive heater had he not been competing with such an elite group. Lefty Welinton Herrera throws from a near sidearm slot but sits in the mid-90s, it’s a pitch that will get him to MLB. Other fastballs with big time power or other standout traits belong to: Zach Agnos, Tyler Burch, Wuardo Fernandez, Jaden Hill, Lebarron Johnson Jr., Alan Perdomo and Jordy Vargas.

#5 – LHP Sean Sullivan

Sullivan is an unusual mention here because of his 89-92 mph fastball, however, he doesn’t need velocity for this pitch to shine. As we have covered at large at BSB, Sullivan does everything else in a crafty, deceptive way. He extends closer to home plate than nearly every pro pitcher while simultaneously getting a one-of-a-kind horizontal angle to the plate by getting his arm way over toward the 1st base dugout.

Additionally, Sullivan throws from a low deceptive slot while also getting solid spin based movement on his fastball. All in all, the fastball shape here is unique and until hitters see Sullivan a handful of times, they’re not gonna see his heater at all. The cherry on top is that Sullivan has pro dart-thrower command and rarely makes a mistake with his fastball.

Sean Sullivan Prospect Profile

#4 – RHP Brody Brecht

The name of Brecht’s game is power. Brecht sits in the upper-90s with his downhill fastball and has touched 103 in-game before, though he’ll usually top out at 100. While Brecht’s fastball doesn’t have the usual modern shape teams are looking for–lots of spin-based movement to sneak up on hitters up in the zone–Brecht takes the opposite approach and leverages his big frame and high arm slot to make his fastball really steep and usually lower in the zone where it generates a high dose of ground balls.

Brecht would likely be higher on the list with more proven command of his heater but he’s probably the second hardest thrower in the organization and found a way to throw more strikes in 2024.

#3 – RHP Seth Halvorsen

Halvorsen was able to make the jump from college to the big leagues in just over one full year, thanks to his fastball that reaches triple digits, topping out at 102. The pitch allowed him to average 11.4 K/9 in the minors last season, and also helped him to strike out 13 batters in 12.1 innings in his MLB cup of coffee. It’s a plus offering that plays at the big league level thanks to overwhelming power, above average extension to home plate, and some life.

Because of his heater, Halvorsen could end up the Rockies closer of the future but he figures to at least provide stable late innings for the club in 2025.

#2 – LHP Luichi Casilla

What Casilla lacks in control, he makes up for in fastball velocity and projectability. The now 20-year-old has been clocked at 100 already and sits mid-90s with his fastball. Casilla stands 6-foot-2, 180 pounds, giving him a little room for growth and potentially even more velocity.

The lefty has an over-the-top windup where his fastball seems to creep up on hitters. In 36 innings pitched last year, Casilla had 57 strikeouts and absolutely overpowered most lower-minors hitters. He will work quickly through the system once he finds the feel for all of his pitches but has a ton of unrealized upside in the meantime.

#1 – RHP Chase Dollander

Dollander is such a good prospect because he executes every component of pitching well. His best skill however, is clearly his fastball. The pitch has been his bread and butter dating back to his collegiate days at Georgia Southern and later at Tennessee with Jacob deGrom-lite comparisons being drawn between his mechanics and pitch quality.

The heater averages 96 mph and tops out at 99. Dollander’s fastball has plenty of carry which helps him generate lots of swing and miss. His solid command and secondaries allow Dollander to get the most out of his fastball, leaving hitters undecided on what pitch is coming. Dollander may have the best overall fastball to reach Coors Field in recent memory in terms of power, shape, and consistency.

Chase Dollander Player Profile

The Rockies have assembled a dynamic assortment of fastballs with multiple of the listed prospects set to throw heat at Coors Field this season.