The 49ers waived Brandon Carswell with an injury designation on Tuesday, the NFL disclosed in its transaction log.
The 24-year-old Carswell suffered an ACL tear last Wednesday, the same day he signed with the club.
Carswell, who played collegiately at Southern Cal, had a brief stint on the Raiders’ practice squad a season ago.
The 49ers now have 11 wide receivers on their roster, including Michael Crabtree, who figures to miss at least a portion of the 2013 campaign after tearing his Achilles in May.