Barraclough was drafted by the St. Louis Cardinals in the seventh round, 240th overall, of the 2012 Major League Baseball draft.[6] He signed with the Cardinals and made his professional debut with the Low-A Batavia Muckdogs. In 15 games between Batavia and the Single-A Quad Cities River Bandits, Barraclough posted a 3.06 ERA with 33 strikeouts. In 2013, he played for the Rookie-level GCL Cardinals, struggling to a 13.50 ERA in 3 appearances and missing most of the season due to injury. He split the 2014 season between the Single-A Peoria Chiefs and the High-A Palm Beach Cardinals, pitching to a cumulative 2–2 record and 2.45 ERA in 48 appearances between the two teams. In 2015, after logging a stellar 0.60 ERA in 11 games for Palm Beach, Barraclough received a promotion to the Double-A Springfield Cardinals, where he was named a Texas League All-Star after recording a 3.28 ERA with 28 strikeouts in 24.2 innings pitched.[7]
Miami Marlins
On July 24, 2015, Barraclough was traded to the Miami Marlins for Steve Cishek.[8] He was called up to the majors for the first time on August 7, 2015.[9] He struck out Joey Terdoslavich for his first Major League strikeout. He finished 2–1 with a 2.59 ERA in 24+1⁄3 innings, he struck out 30 while issuing 18 walks. In 2016, he struck out 113 in just 72+2⁄3 innings. He also issued 44 walks. The next season he appeared in 66 games, striking out 76 in 66 innings. On June 3, 2018, he replaced Brad Ziegler as closer.[citation needed]
On August 9, 2019, the San Francisco Giants claimed Barraclough from the Nationals off of waivers.[12] On August 15, Barraclough was designated for assignment. He was outrighted to the Triple-A Sacramento River Cats on August 16.[13] On September 2, the Giants selected Barraclough's contract. Barraclough was designated for assignment on October 30 and elected free agency on November 1.[14]
San Diego Padres
On December 17, 2019, Barraclough signed a minor league contract with the San Diego Padres organization. Barraclough did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.[15] He elected free agency on July 14, 2020.
New York Yankees
On February 2, 2021, Barraclough signed a minor league contract with the New York Yankees organization and was invited to Spring Training.[16] Barraclough pitched to a 3.21 ERA in 14.0 innings of work for the Triple-A Scranton/Wilkes-Barre RailRiders, but was released on June 18, 2021.[17][18]
Minnesota Twins
On June 20, 2021, Barraclough signed a minor league contract with the Minnesota Twins organization and was assigned to the Triple-A St. Paul Saints.[19] After posting a 2.86 ERA with 31 strikeouts and 18 appearances for St. Paul, the Twins selected Barraclough's contract on August 19. Barraclough entered in relief for the Twins against the Yankees on August 20. [20] Barraclough made 10 appearances for the Twins, going 2–0 with a 5.54 ERA and 18 strikeouts. On October 8, Barraclough was outrighted off of the 40-man roster.[21] On October 14, Barraclough elected free agency.[22]
Los Angeles Angels
On January 13, 2022, Barraclough signed a minor league contract with the Los Angeles Angels.[23] He was assigned to the Triple-A Salt Lake Bees to begin the year.
On May 7, 2022, Barraclough was selected to the 40-man and active rosters.[24] Barraclough was designated for assignment on June 27 after Dillon Thomas was claimed off waivers.[25] He was outrighted off the roster on June 30. He finished the season at 0–1 record with a 3.00 ERA and nine strikeouts in eight games.[1] In 41 appearances for Salt Lake, Barraclough recorded a 3.00 ERA with 61 strikeouts and 2 saves in 45.0 innings pitched. On October 14, Barraclough elected to become a free agent.
On June 19, 2023, Barraclough signed a minor-league contract with the Boston Red Sox organization.[27] Barraclough was assigned the Red Sox Triple-A affiliate, the Worcester Red Sox. He enjoyed success in Worcester, going 7–0 with a 2.57 ERA in eight appearances, including seven starts. On August 9, his contract was selected and he was promoted to the major leagues.[28] He made his Red Sox debut on August 11 in relief against the Detroit Tigers, pitching 1+1⁄3 scoreless innings with three strikeouts and earning the win. He was optioned back to Worcester on August 13, as Garrett Whitlock was activated from the injured list,[29] and recalled again on August 28.[30] Barraclough was hit hard during his second call-up, as Red Sox manager Alex Cora left him in a game against the Houston Astros (whom the Red Sox were pursuing for a postseason wild card berth) for 4+1⁄3 innings during which he threw a career-high 94 pitches while allowing 11 hits and 10 earned runs, while also hitting three batters. The decision was attributed to the majority of Boston's bullpen being tired, leaving Barraclough to pitch multiple innings despite the outcome.[31] Cora gave Barraclough the option to end his outing before the ninth inning and have a position player pitch, but Barraclough declined and finished the game.[32] Barraclough was optioned back to Worcester the next day.[33] On September 24, Barraclough was designated for assignment following the activation of Zack Kelly from the injured list.[34] On September 26, he cleared waivers and was subsequently outrighted to Worcester.[35] Barraclough elected free agency on October 10.[36]