 On December 17, 2007, the Atlanta Falcons promoted Grimes to their active roster after cornerback Lewis Sanders tore his pectoral muscle and was placed on injured reserve.On December 12, 2007, head coach Bobby Petrino resigned from his position after only 13 games where the Falcons finished with a 3–10 record.Petrino decided to accept the vacant head coaching job at Arkansas after quarterback Michael Vick was arrested for operating an unlawful interstate dog fighting venture.