Dolphins sign Austin, send Martin to IR

The Miami Dolphins placed defensive tackle Vaughn Martin on injured reserve Tuesday, while signing former second-round draft choice Marvin Austin to fill his roster spot.

Austin, selected 52nd overall by the Giants in the 2011 draft, had been waived by New York during final roster cuts. The injury-prone lineman appeared in just eight games over his two seasons with the Giants, spending his entire rookie campaign on IR and making eight tackles as a reserve last year.

The 24-year-old Austin also sat out his senior season at the University of North Carolina in 2010, having being suspended for receiving improper benefits following an extensive NCAA investigation of the Tar Heels' program.

Martin signed with Miami in March after spending his first four NFL seasons with San Diego, but managed just one tackle in a backup role through the first three games. The Canadian-raised 27-year-old had started 27 games for the Chargers over the previous two years.

The Dolphins did not disclose the exact nature of Martin's injury.