St. Louis Cardinals

On November 29, 2017, Pacheco signed with the St. Louis Cardinals as an international free agent. He spent his first professional season with the Dominican Summer League Cardinals and Gulf Coast League Cardinals, posting a 1.05 ERA across 20 appearances. In 2019, he made 41 appearances for the Single–A Peoria Chiefs, logging a 4.12 ERA with 90 strikeouts in 54+2⁄3 innings pitched.^[1]

He did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.^[2] Pacheco's 2021 season was split between High–A Peoria, the Double–A Springfield Cardinals, and the Triple–A Memphis Redbirds. In 41 appearances out of the bullpen, he registered a cumulative 3.67 ERA with 95 strikeouts and 11 saves in 54.0 innings pitched.^[3]

On November 19, 2021, the Cardinals added Pacheco to their 40-man roster to protect him from the Rule 5 draft.^[4] He split the 2022 season between Springfield and Memphis, posting a combined 3.05 ERA with 84 strikeouts and 12 saves in 62.0 innings pitched.^[5] Pacheco was optioned to Triple-A Memphis to begin the 2023 season.^[6]

Detroit Tigers

On March 14, 2023, Pacheco was claimed off waivers by the Detroit Tigers.^[7] On March 27, Pacheco was placed on the 60-day injured list with a right elbow injury.^[8] On June 5, he underwent Tommy John surgery, ending his season.^[9] On November 14, Pacheco was designated for assignment after multiple prospects were added to the roster.^[10] Three days later Pacheco became a free agent when he was not tendered a contract from the Tigers.^[11]

On December 13, 2023, Pacheco re–signed with the Tigers on a minor league contract.^[12] He started the 2024 minor league season on the 7 day IL.