Contreras signed with the New York Yankees as an international free agent on July 2, 2016.[1][2] He split his professional debut season of 2017 between the DSL Yankees and the rookie–level GCL Yankees, going a combined 4–4 with a 4.02 ERA and 34 strikeouts over 53+2⁄3 innings. Contreras split the 2018 season between the Low–A Staten Island Yankees and the Single–A Charleston RiverDogs, going a combined 0–2 with a 2.42 ERA and 60 strikeouts over 63+1⁄3 innings. He returned to Charleston for the 2019 campaign, going 12–5 with a 3.33 ERA and 113 strikeouts over 132+1⁄3 innings. He did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.[3] On November 20, 2020, the Yankees added Contreras to their 40-man roster to protect him from the Rule 5 draft.[4]
On September 29, 2021, Contreras had his contract selected to the active roster, to make his MLB debut that night versus the Chicago Cubs.[9] Contreras started the 2022 season in Triple-A Indianapolis, but on April 8, 2022, the Pirates recalled him from the minor leagues.[10] On April 14, Contreras earned his first major league win in a 9–4 victory over the Washington Nationals.[11] In 21 games for the club, he registered a 5–5 record and 3.79 ERA with 86 strikeouts across 95 innings of work.[12]
In 2023, Contreras made 19 appearances (11 starts) for Pittsburgh, but struggled to a 3–7 record and 6.59 ERA with 55 strikeouts across 68+1⁄3 innings pitched.[13] Out of options entering the 2024 season, Contreras became a relief pitcher.[14] In 12 outings, he registered a 4.41 ERA with 16 strikeouts across 16+1⁄3 innings pitched. On May 11, 2024, Contreras was designated for assignment following the promotion of Paul Skenes.[15]
Los Angeles Angels
On May 16, 2024, Contreras was traded to the Los Angeles Angels in exchange for cash considerations.[16][17] In 37 appearances for the Angels, Contreras compiled a 1–4 record and 2.33 ERA with 40 strikeouts and 2 saves across 52 innings of work.
Texas Rangers
On October 31, 2024, Contreras was claimed off waivers by the Texas Rangers.[18]