Seth Michael Halvorsen...Son of Lisa and Brent Halvorsen...Has two sisters, Mariah and Ainsley, and a brother, Nathan...Originally drafted in the 30th round of the 2018 First-Year Player Draft by the Minnesota Twins and in the 19th round of the 2021 First-Year Player Draft by the Philadelphia Phillies, but did not sign to either team...Transferred to the University of Tennessee in 2021 and missed his 2022 season due to an injury...Went 3-3 with a 3.81 ERA (52.0 IP, 22 ER) with 16 walks and 52 strikeouts for his junior season in 2023...Spent his first three collegiate seasons at University of Missouri from 2019-2021, combining to go 4-2 with a 5.82 ERA (77.1 IP, 50 ER) with 63 walks and 72 strikeouts in 18 appearances (14 starts)...Underwent Tommy John surgery as a freshman in 2019...Named the 2018 Minnesota Gatorade Player of the Year and was on the 2018 Rawlings/Perfect Game First Team All-American...Was a two-player in his senior season at Heritage Christian Academy (Minn.)...Batted .405 with 29 stolen bases, while going 7-1 with a 0.94 ERA and 117 Ks on the mound that season.
2025
Went 11-for-14 in save opportunities, the most saves for a rookie reliever in 2025… tied with Carlos Estévez (2016) for the most saves for a rookie in a single season in franchise history...Made the Opening Day roster for the first time and remained with the club throughout the season … placed on the 15-day injured list on Aug. 3 (strained right elbow) and missed the remainder of the season...His 42 appearances tied for the 10th most among NL rookie arms...His 103.3 MPH pitch in the bottom of the ninth inning on July 3 vs. Houston was the fastest pitch by a Rockie in the Statcast Era (since 2015) … broke his own record set on May 16 at Arizona (102.9) … ranked as the 10th-fastest pitch thrown in the NL in 2025...Averaged 100 MPH on his fastball, the third-fastest fastball average among all pitchers (min. 150 BF) … threw 190 pitches of 100 MPH or faster in 2025, the fourth most among Major League relievers...Posted a 3.24 ERA (16.2 IP, 6 ER) across his first 16 games of the season through May 11 … 6.24 ERA (23 IP, 16 ER) through his last 26 games … nine earned runs through two outings: four on May 19 vs. Philadelphia and a career-high five on July 9 at Boston...Season-high three strikeouts on May 7 vs. Detroit, tying a career high...In his 11 games with a recorded save, posted a 1.54 ERA (11.2 IP, 2 ER) with zero home runs allowed...In 24 games while pitching in the ninth inning, held opponents to a .192/.312/.295 slash line, striking out 21 while recording a 2.42 ERA (22.1 IP, 6 ER)...In six games on zero days rest, posted a 1.59 ERA (5.2 IP, 1 ER) while holding opposing hitters to a .059/.185/.235 slashline.
2024
Began his season in Double-A and ascended to make his Major League debut with Colorado on Aug. 30, becoming the first Rockie from the 2023 draft class to make his debut...Combined for a 5-2 record with nine saves and a 4.47 ERA (44.1 IP, 22 ER) in 41 games between Double-A Hartford (33 G) and Triple-A Albuquerque (8 G)...Recorded his first Major League win on Sept. 12 at Detroit and his first Major League save on Sept. 21 at Los Angeles-NL...Did not allow an earned run through his first nine career Major League outings, one of three Rockies all-time to allow no earned runs through their first nine games to start their career (also: Luis Peralta, 2024 & Ramón Ramírez, 2016)...Scoreless in 10 of his 12 outings with Colorado, finishing 2-1 with a 1.46 ERA (12.1 IP, 2 ER) with 13 strikeouts, two walks and two saves...Threw 47 pitches 100 MPH or faster during the season, including a 102.5 MPH fastball on Sept. 26...It was the second-fastest pitch by a Rockie in the Statcast Era (since 2015).
