The Chicago Cubs have added another experienced arm to their growing bullpen competition, agreeing to a minor-league contract with right-handed reliever Trent Thornton that includes a non-roster invitation to major league spring training. The agreement was first shared publicly by Tread Athletics last week, and Chicago radio insider Bruce Levine confirmed the news on Wednesday.
Thornton, 32, brings seven seasons of major league experience split between the Toronto Blue Jays and Seattle Mariners. Over 235 career appearances, he owns a 14–19 record with a 4.38 ERA, striking out 379 hitters in 401 innings. His most productive stretch came with Seattle, where he posted a 3.65 ERA across 140 2/3 innings from 2023 through 2025, including 127 appearances and 130 strikeouts.
Thornton's 2025 season was cut short on July 31 after he tore his left Achilles while covering first base on a ground ball against the Texas Rangers, sidelining him for an estimated six to eight months. At the time of the injury, the right-hander was 2–0 with a 4.68 ERA in 33 appearances. Thornton is “ahead of schedule” in his rehabilitation, according to Tread Athletics. He has already resumed throwing bullpen sessions and is likely to be healthy for spring training.
Thornton originally entered the majors as a starter with Toronto, making 29 starts and pitching 154 1/3 innings during his 2019 rookie season. After things didn't go his way in the shortened 2020 campaign, he transitioned full-time to relief work in 2021.
Although he never quite found consistent results with the Blue Jays, where he had a 4.77 ERA across parts of five seasons, the change of scenery in Seattle made a real difference. In 2023, he put together a 2.08 ERA in 26 innings, followed by a 3.61 ERA over 72 1/3 innings the next season.
During his time with the Mariners, Thornton struck out 22.5% of opposing hitters while walking just 6.6%. He worked primarily off a mid-80s slider, throwing it nearly 52% of the time, while averaging 95.5 mph with his fastball during the 2024 season. His ground-ball rate over that stretch sat at 39.7%.
Thornton now enters a competitive Cubs bullpen picture. Chicago has already added Phil Maton, Hunter Harvey, Jacob Webb, and Hoby Milner, while re-signing left-hander Caleb Thielbar. Other minor league signees include Charlie Barnes, Corbin Martin, Jeff Brigham, and Collin Snider.
With recent contributors Andrew Kittredge and Drew Pomeranz departed, the Cubs are again looking for value finds, following last season's success with Brad Keller. Thornton will attempt to follow that same path, competing for a role as spring training gets underway.
