Aldegheri played for the Parma Clima of the Italian Baseball League in 2019 and 2020. In July 2019, he signed with the Philadelphia Phillies as an international free agent.[2] He made his professional debut in 2021 with the Rookie-levelFlorida Complex League Phillies before being promoted to the Low-AClearwater Threshers. He was placed on the injured list with a left elbow injury on August 20 and missed the remainder of the season and a portion of the following season, which he spent exclusively in the Florida Complex League.[3]
Aldegheri returned to Clearwater for the start of the 2023 season before being promoted to the High-AJersey Shore BlueClaws on August 3.[3] After the 2023 season ended, his control was ranked the best in the Phillies farm system by Baseball America.[3] Aldegheri returned to Jersey Shore for the start of the 2024 season.[4]
On 29 August 2024, the Angels called Aldegheri up to the major leagues for the first time.[7] While other Italian-born pitchers had previously appeared in the major leagues, such as Marino Pieretti,[8] Aldegheri became the first pitcher born and raised in Italy to appear in an MLB game,[9] when he made his debut with the Angels on 30 August.[10]