Guerra is notable for his development of a split-finger fastball, a pitch which he learned while playing in the Venezuelan Professional Baseball League and ultimately led to his 2015 rise to the MLB. Guerra said of the pitch in 2017, "I have no idea where I would be without it."[1]
In October 2001, the Atlanta Braves signed the then 16 year old Guerra, as an international free agent out of Venezuela, to play as a catcher. After being converted to a pitcher in 2006,[2] he was released by the Braves and signed with the New York Mets in 2008, where he gained traction but failed a PED test in 2009.[3]
Guerra was called up to the majors for the first time on June 7, 2015.[10] He made his major league debut a few days later on June 12, and pitched in a total of three games with the White Sox.
On October 7, 2015, Guerra was claimed off waivers by the Milwaukee Brewers as the first roster move of general manager David Stearns.[11] The Brewers chose to make him a starting pitcher rather than a reliever.
Guerra experienced success in his first season with the Brewers, posting a 9–3 pitching record and a 2.81 ERA over 20 games. His rookie season, at the age of 31, resulted in accolades including the BBWAA naming Guerra the Brewers' Most Valuable Pitcher of 2016.[12]
A shoulder injury kept Guerra out of play in August 2016 and forced him to skip winter league baseball in the 2016–17 offseason.[13] Despite that, Guerra earned his spot in the rotation with a consistent 2016 season in the majors.[14]
On April 3, 2017, Guerra was the starting pitcher for the Brewers on Opening Day.[15] He left after three innings with a strained right calf, an injury suffered while bunting in the 3rd inning.[16]
Guerra did not return for the Brewers until late May and struggled to return to his 2016 form. He posted a 5.85 ERA in June, and was subsequently optioned to the minor leagues.[17] Guerra returned but finished his season with a disappointing 1–4 record and career-worst 5.12 ERA in 21 games.[18]
The Brewers hoped Guerra could return to his 2016 season form for 2018, and Guerra did have mostly successful outings in 2018 at the beginning of the season. On May 30, 2018, Guerra pitched six shutout innings against the St. Louis Cardinals and allowed no walks.[19] Guerra avoided the major injury problems that plagued him in prior seasons, appearing in a then-career best 31 games, but finished the 2018 campaign with a 6–9 record and a 4.09 ERA.
Guerra was transitioned to a relief role for the 2019 season and led the National League in relief innings pitched at 83+2⁄3. Guerra appeared in 72 games for Milwaukee, securing a 9–5 record and 3.55 ERA, while also notching the first three saves of his career.[20]
Guerra was non-tendered on December 2, 2019, and became a free agent.[21]
On December 9, 2019, Guerra signed a one-year contract, with a club option, with the Arizona Diamondbacks.[22] On July 5, 2020, it was announced that Guerra had tested positive for COVID-19.[23] On November 20, 2020, Guerra was designated for assignment.[24] On November 23, Guerra was released by the Diamondbacks.[25] In 25 games for Arizona, he was 1–2 with a 3.04 ERA in 23+2⁄3 innings.
On January 30, 2021, Guerra signed a minor league contract with the Los Angeles Angels organization and was invited to Spring Training.[26] On March 16, 2021, the Angels selected Guerra's contract to the 40-man roster.[27] Guerra made 41 appearances for the Angels in 2021, struggling to a 6.06 ERA with 61 strikeouts in 65.1 innings pitched. He was designated for assignment following the season on November 16, 2021.[28] He was released by the Angels three days later.[29]
On March 8, 2022, Guerra signed with the Tecolotes de los Dos Laredos of the Mexican League.[30] Guerra started 16 games for Dos Laredos in 2022, pitching to an 8–3 record and 3.56 ERA with 87 strikeouts in 83.1 innings of work. On February 3, 2023, Guerra was released by the team after undergoing elbow surgery.[31]
On January 8, 2024, Guerra re–signed with the Tecolotes after a season of inactivity.[32]
