Guerrieri started the 2013 season with a 6–2 win–loss record and a 2.01 ERA in 14 games started with the Bowling Green Hot Rods of the Class AMidwest League.[2] He was chosen to represent the Rays at the 2013 All-Star Futures Game.[5] He reported fatigue in his arm in June and was given two weeks off.[6]C. J. Riefenhauser replaced Guerrieri at the Futures Game.[7] He then lasted only two innings after suffering elbow discomfort in his throwing arm. He underwent Tommy John surgery to repair a torn ulnar collateral ligament in his elbow on July 24, 2013.[6] He received a 50-game suspension after the 2013 season, which he served while rehabilitating from surgery, for using a substance of abuse.[2][8]
On November 5, 2017, the Toronto Blue Jays acquired Guerrieri on waivers.[14] He pitched for the Buffalo Bisons of the International League in 2018. The Blue Jays promoted him to the major leagues on September 1, 2018.[15] On November 2, Guerrieri cleared waivers and entered free agency.[16]
Texas Rangers
On January 9, 2019, the Texas Rangers signed Guerrieri to a minor league contract with an invitation to spring training.[17] He was assigned to the Triple-ANashville Sounds to open the 2019 season.[18] On July 16, the Rangers selected Guerrieri's contract.[19] Guerrieri was designated for assignment on November 20, 2019.[20] He accepted an outright assignment to Nashville on November 27.[21] Guerrieri elected free agency after the 2020 season on October 1, 2020.
Seattle Mariners
On February 8, 2021, Guerrieri signed a minor league contract with an invitation to Spring Training with the Seattle Mariners.[22] Guerrieri appeared in 22 games with the Triple-A Tacoma Rainers, recording a 4.61 ERA with 28 strikeouts. On August 12, 2021, Guerrieri was released by the Mariners.
Philadelphia Phillies
On August 24, 2021, Guerrieri signed a minor league contract with the Philadelphia Phillies organization. He was assigned to the Triple-A Lehigh Valley IronPigs,[23] where he made 7 appearances and struggled to a 6.48 ERA with 10 strikeouts in 8.1 innings pitched. He elected free agency following the season on November 7.[24]