Crocker is the third free agent defensive back to sign with the Dolphins this offseason, following safety Keith Davis and cornerback Nathan Jones. Both Davis and Jones played for Dallas last season.Crocker, meanwhile, started the last two seasons with Atlanta after playing three years with Cleveland.
Crocker was a third-round pick of the Browns in 2003 but was traded to Atlanta for a fourth-round pick in March of 2006.
His best season came in 2005 when he had 79 tackles, two sacks, one interceptions and two forced fumbles.