Horn sustained a torn quadriceps during the fourth quarter of Sunday's 21-18 loss to the Browns and is expected to miss 6-to-12 weeks, Mike Kaye and Jeremy Fowler of ESPN.com report.
Horn plans to seek a second opinion before establishing a treatment plan for the injury, which could include surgery. Regardless, the two-time Pro Bowler will be headed for injured reserve, with his loss further weakening an already depleted Carolina defensive backfield. Along with Horn, Mike Jackson (groin) exited Sunday's game with an injury, so Carolina could need to break in two new starting cornerbacks Week 4 against the Lions.