Sean Sullivan, the No. 11 prospect in Colorado Rockies' system, will make his MLB debut against Athletics.
Sean Sullivan has gotten the call. He's heading on up to the MLB level.
On Friday, the Colorado Rockies announced a series of roster moves.
Sullivan, the No. 11 prospect in the Rockies' system, is coming to join the major-league club in Las Vegas. He's scheduled to see his first MLB action on Friday night, when the Rockies open a three-game series at Las Vegas Ballpark against the Athletics.
In other moves, left-handed pitcher Sammy Peralta was optioned to Triple-A Albuquerque. Additionally, right-handed pitcher Chase Dollander was transferred to the 60-day Injured List.
Sullivan is Rockies' No. 11 Prospect
According to the Rockies' communications office, Sullivan, 23, is currently ranked by MLB.com as the Rockies' No. 11 prospect. He made 11 starts with Triple-A Albuquerque in 2026, going 5-3 with a 5.60 ERA (54.2 innings, 34 earned runs), 19 walks and 50 strikeouts.
Sullivan enters Friday's action ranked at No. 7 in the hitter-friendly Pacific Coast League in strikeouts.
In four Minor League seasons (2023-26), Sullivan gone 24-11 with a 3.08 ERA (278.0 innings pitched, 95 earned runs), 60 walks, and 289 strikeouts in 55 games (52 starts).
Sullivan's 9.36 K/9 ranks third among Rockies Minor League pitchers since 2023 (minimum 250 innings pitched). He was named the 2024 Northwest League Pitcher of the Year after going 7-2 with a 2.16 ERA (83.1 innings pitched, 20 earned runs) and 101 strikeouts over 14 starts for High-A Spokane.
He also was named as a Northwest League Postseason All-Star and a Baseball America High Class A All-Star. Sullivan, a native of Boston, Mass, was originally selected by Colorado in the second round of the 2023 First-Year Player Draft out of Wake Forest.
Peralta Goes Back Down
Peralta was just recalled from Albuquerque last Sunday, marking his third appearance on the Rockies' active MLB roster. Peralta made his Rockies debut back on May 19 and was that game's opening pitcher. It was his first MLB start and first MLB game overall since Sept. 28, 2025, when he was on the Los Angeles Angels' staff.
He was claimed by Colorado off waivers from the Milwaukee Brewers on April 4 and was immediately assigned to the Isotopes.
In 18 games with Albuquerque, Peralta is 7-1 with a 4.50 ERA (28.0 IP, 14 ER) with six walks and 22 strikeouts. He also made two appearances with the Brewers' Triple-A Nashville club before being acquired by Colorado, allowing three runs over 1.0 IP.
The Rockies start a six-game road trip in Las Vegas. Colorado is coming off its sixth series win this season, taking two of three games against the Chicago Cubs at Coors Field in Denver. Colorado has won three of its past four series since May 19.
Additionally, the ballclub's six series wins before the All-Star break are the most since the Rockies won 10 first-half series in 2023.
Colorado hopes to get off on a winning foot against the Athletics. One thing that has been noticed by many around MLB is how Las Vegas Ballpark has become some type of launching pad, where home runs travel deep into the night.
Maybe a Rockies player can step to the plate and drive a pitch out, too.
