Rasmussen spent his first professional season in 2019 with the Single–A Wisconsin Timber Rattlers, High–A Carolina Mudcats, and Double–A Biloxi Shuckers. In 27 games (23 starts) split between the three affiliates, he compiled a 1–3 record and 3.15 ERA with 96 strikeouts across 74+1⁄3 innings pitched.[9]
On August 13, 2020, Rasmussen was selected to the 40-man roster and promoted to the major leagues for the first time. He made his major league debut on August 19 against the Minnesota Twins and threw two scoreless innings. In 12 games during his debut campaign, Rasmussen posted a 5.87 ERA with 21 strikeouts across 15+1⁄3 innings pitched.[10] Rasmussen began the 2021 season in the Milwaukee bullpen. He recorded a 4.24 ERA with 25 strikeouts and one save in 15 games for the Brewers.
Tampa Bay Rays
On May 21, 2021, the Brewers traded Rasmussen and J. P. Feyereisen to the Tampa Bay Rays in exchange for Willy Adames and Trevor Richards.[11] In 20 appearances (10 starts) down the stretch, he logged a 4–0 record and 2.44 ERA with 48 strikeouts.
Rasmussen pitched eight perfect innings before losing the perfect game in the ninth inning on August 14, 2022.[12] In 2022, Rasmussen was named American League Pitcher of the Month for August, when he registered a 3–1 record in six starts to go along with a 1.57 ERA and 33 strikeouts against only four walks.[13] He finished the 2022 season making 28 starts for the Rays, and pitched to a 11–7 record and 2.84 ERA with 125 strikeouts in 146.0 innings pitched.
Rasmussen began the 2023 season out of the Rays' rotation, making 8 starts and registering a 4–2 record and 2.62 ERA with 47 strikeouts in 44.2 innings pitched. On May 12, 2023, Rasmussen was placed on the 60-day injured list after being diagnosed with a flexor strain in his forearm.[14][15] On July 8, Rays manager Kevin Cash stated that Rasmussen would undergo an internal brace procedure on his elbow and miss the remainder of the season.[16][17]
Rasmussen began the 2024 season on the Rays' 60-day injured list as he continued to recover from surgery.[18] He was activated from the injured list on August 7, 2024.[19]
Personal life
Rasmussen and his wife, Stevie, married in 2020.[20] They had a son on September 6, 2022.[21]