The Chicago White Sox selected Sousa in the 10th round of the 2018 MLB draft.[3] In 20 games, Sousa posted a 2–0 win–loss record and a 1.27 earned run average (ERA). In 2019, Sousa posted an ERA of 2.49 in 43 games with Kannapolis, Winston-Salem, and Birmingham. Sousa was added to the Glendale Desert Dogs roster for 2019 where he posted a 5.59 ERA in 9 games. Sousa did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.[4] In 2021, Sousa posted a 3.61 ERA in 41 games while striking out 71 batters in 47+1⁄3 innings.
The White Sox added Sousa to their 40-man roster after the 2021 season.[5] He was named to the Opening Day roster for the 2022 season.[6] Sousa made his MLB debut on April 8, 2022, pitching a scoreless inning out of the bullpen.[7] Despite having a 3–0 record, after appearing in 25 games and having an ERA of 8.41, Sousa was sent back to Triple-A on June 14.
On February 20, 2023, Sousa was designated for assignment after the signing of Elvis Andrus was made official.[8]
Cincinnati Reds
On February 22, 2023, Sousa was claimed off waivers by the Cincinnati Reds.[9] Sousa was optioned to the Triple-A Louisville Bats to begin the 2023 season.[10] On April 5, Sousa was designated for assignment following the promotion of Kevin Herget.[11]
Milwaukee Brewers
On April 9, 2023, Sousa was traded to the Milwaukee Brewers in exchange for cash considerations and international bonus pool space.[12] He made two appearances for Milwaukee before he was placed on the injured list with left shoulder nerve irritation on June 9.[13] Sousa was transferred to the 60–day injured list on July 28.[14] He was activated on August 7, and optioned to the Triple–A Nashville Sounds.[15]
On September 3, 2023, Sousa was claimed off waivers by the Houston Astros.[18] He made five scoreless appearances for Houston, registering 8 strikeouts across 6+1⁄3 innings pitched.
On April 4, 2024, Sousa underwent surgery to address thoracic outlet syndrome, ruling him out for the entirety of the season.[19]