Dolphins' CB Richard Marshall on IR

One of the Miami Dolphins’ biggest free-agent signings is done for the season.

The Dolphins put starting cornerback Richard Marshall on injured reserve due to a continuing back injury. Marshall has been out since Week 4. He continued to rehab and thought he could return after Miami’s bye week. But Marshall continues to struggle with his back and the team decided this week to shut him down.

Miami signed Marshall to a three-year, $16 million contract in the offseason.

The Dolphins are struggling in its secondary with lack of depth and inconsistent play. The Dolphins claimed cornerback Brandon McDonald off waivers from the Tampa Bay Buccaneers.