At 19, Rosso was signed by the Los Angeles Dodgers for a signing bonus of $62,000 on July 2, 2015. He was released by the Dodgers a year later on July 15, 2016, and never pitched in a minor league game for the organization.[1][2]
Rosso was signed by the Philadelphia Phillies, who had offered him a contract prior to his signing with the Dodgers, on June 2, 2017.[1] He debuted for the Dominican Summer League Phillies, pitching to a 6–1 win–loss record with a 0.74 earned run average (ERA) in nine starts and earning a promotion to the Gulf Coast League Phillies.[3] After striking out 13 batters with one earned run in nine innings pitched, Rosso was again promoted and finished the season with the Williamsport Crosscutters of the New York–Penn League.[2] He posted a 1–0 record with a 3.00 ERA and 23 strikeouts in 18 innings pitched with Williamsport.[4] Rosso began the 2018 season with the Lakewood BlueClaws of the South Atlantic League, where he went 5–1 with a 1.33 ERA and 81 strikeouts in 12 starts and was named a league All-Star before being promoted to the Clearwater Threshers of the Florida State League. He pitched in 11 games with 10 starts for Clearwater and went 6–2 with a 2.91 ERA.[5] Rosso began 2019 with the Reading Phillies of the AA Eastern League, where he had a 3–2 record with a 3.15 ERA in ten starts before earning a promotion to the AAA Lehigh Valley IronPigs.[6] He finished the season with Lehigh Valley and went 2–4 with a 5.50 ERA and 64 strikeouts.[7]
Rosso was invited to Spring Training by the Phillies in 2020.[8][9] On July 24, 2020, he made his MLB debut. He finished his rookie season with a 6.52 ERA in 7 appearances. He pitched 1.1 scoreless innings for the Phillies in 2021 before being designated for assignment on May 23, 2021.[10] He was outrighted to Triple-A Lehigh Valley on May 28.[11] On September 1, 2021, the Phillies selected Rosso's contract.[12] On November 5, 2021, Rosso was outrighted off of the 40-man roster and elected free agency.[13]
On March 14, 2022, Rosso signed a minor league deal with the Detroit Tigers.[14] He made only one appearance for the Triple–A Toledo Mud Hens, tossing a scoreless inning and recording one strikeout. Rosso was released by the Tigers organization on May 27.
On February 1, 2024, Rosso signed with the Piratas de Campeche of the Mexican League.[15] In nine starts, he posted a 1–7 record with a 7.05 ERA and 33 strikeouts over 37.0 innings. On June 13, 2024, Rosso was released by Campeche.[16]
On June 20, 2024, Rosso signed with the Bravos de León of the Mexican League.[17] He made one start, giving up 4 earned runs in 2+1⁄3 innings. On July 1, Rosso was released by León.[18]
