In 2017, Beeks played for Portland and the Pawtucket Red Sox of the Triple–AInternational League.[7] The Red Sox named him their Minor League Pitcher of the Year[8] after he posted a combined 11–8 record, 3.29 ERA, and 1.21 WHIP in 26 games started between the two teams.[9] The Red Sox added Beeks to their 40-man roster after the 2017 season.[10] He began the 2018 season with Pawtucket.[11]
Beeks was promoted to Boston's active roster on June 7, 2018,[12] in order to make his MLB debut in a start against the Detroit Tigers.[13] Beeks gave up five first-inning runs and took the loss;[14] he was optioned back to Pawtucket the next day.[12] Beeks was recalled to Boston on July 10; he pitched 2+1⁄3 innings that day, allowing four hits and three runs, and was then returned to Triple-A.[15]
Tampa Bay Rays
On July 25, 2018, the Red Sox traded Beeks to the Tampa Bay Rays in exchange for right-handed pitcherNathan Eovaldi.[16] With the Rays, Beeks made 12 appearances through the end of the season, compiling a 5–0 record with a 4.47 ERA and 37 strikeouts in 44+1⁄3 innings.
Beeks began the 2019 season with Tampa Bay.[17] He was optioned to the Triple-A Durham Bulls on June 28,[18] and was recalled on July 16.[19] He finished the season with a 6–3 record, 4.31 ERA, 1.49 WHIP and 89 strikeouts over 104+1⁄3 innings at the MLB level.[20]
On August 25, 2020, Beeks tore his ulnar collateral ligament while pitching against the Baltimore Orioles, ending his season and requiring Tommy John surgery.[21] On February 17, 2021, Beeks was placed on the 60-day injured list as he continued to recover from Tommy John surgery.[22]
On March 22, 2022, Beeks signed a $750,000 contract with the Rays, avoiding salary arbitration.[23] On June 4, Beeks, along with 4 other Rays teammates, opted out of wearing a Rays team logo and cap in support of LGBTQ+ Pride, during the team's annual Pride Night celebration at Tropicana Field.[24] In 42 appearances for the club in 2022, he registered a 2.80 ERA with 70 strikeouts and 2 saves in 61.0 innings of work.[25]
In 2023, Beeks made 30 appearances for the Rays, but struggled to a 5.95 ERA with 47 strikeouts across 42+1⁄3 innings pitched. Following the season on November 4, Beeks was removed from the 40–man roster and placed on outright waivers.[26]
Colorado Rockies
On November 6, 2023, Beeks was claimed off waivers by the Colorado Rockies.[27] In 45 appearances for Colorado in 2024, Beeks compiled a 6–4 record and 4.74 ERA with 38 strikeouts and 9 saves.