The 49ers waived Alonso (knee) with a failed physical designation Monday, Adam Caplan of SiriusXM NFL Radio reports.
Alonso tore his ACL back in January and began the 2020 season on the reserve/PUP list. He returned to practice Oct. 19 but was traded from New Orleans to San Francisco on Nov. 2. His practice period expired Nov. 14, meaning he would reside on PUP for the rest of the season unless the 49ers cut him, which they opted to do Monday. Once Alonso is healthy, he can sign with another team.