The Best Reliever You Haven't Heard Of
Rockies flamethrower, Seth Halvorsen, is poised for a big 2025.
Seth Halvorsen was the Rockies 7th round pick in 2023 out of the University of Tennessee. Rising quickly through the system, Halvorsen made his major league debut in 2024 after only 57 2/3 career minor league innings. His success carried over at the MLB level where, in limited action, he threw 12 1/3 innings giving up 8 hits, 2 walks, 13 strikeouts, and only 2 earned runs. Both of the earned runs came on back-to-back 9th inning solo home runs by Shohei Ohtani and Mookie Betts to tie and then win the September 22nd contest in Los Angeles.
In a largely inexperienced Rockies bullpen, Halvorsen is slated to compete with Victor Vodnik and veteran Tyler Kinley for the closing role. What makes Halvorsen such an intriguing piece is his electric fastball. At the MLB level in 2024, his four-seam fastball averaged 99.9 mph and his sinker averaged 100.1. Rounding out his arsenal is a pair of high 80s secondary pitches in his splitter and slider.
Using Fangraphs’ Pitching+, Halvorsen grades out at 121, which puts him 10th among all pitchers last year with at least 10 innings pitched (qualified leader was Corbin Burnes, 119). For pitchers that are currently rostered by the Rockies, Victor Vodnik ranks second with a 100. In comparison, other late season call ups for the Rockies, Jaden Hill (10 2/3 innings) and Luis Peralta (12 1/3) each posted a Pitching+ of 82. Individually, three of Halvorsen’s pitches grade out above average using Stuff+ with his four-seam at 103, sinker at 119, and his slider at 124. His splitter tracks slightly below the average of 100 at 98.
Enjoy this video of Halvorsen spotting up 101 mph to complete the strikeout (from Pitching Ninja X/Twitter:
As the Rockies head into 2025, they will look to continue developing Halvorsen, and the team has already begun acclimating him to high-leverage situations. In 2024, 8 of Halvorsen’s 12 appearances were in the 9th inning, showcasing the team’s quick trust in his ability to handle pressure. He converted 2 of 3 save opportunities, and with his electric arsenal and an impending full season workload, the Rockies have high hopes for him. The Rockies 2025 bullpen is full of young flamethrowers looking to prove themselves and Halvorsen has the ability to be the best of the bunch.