On January 5, 2007, Bill Cowher resigned as head coach of the Steelers. In the press conference that followed, Steelers' president Art Rooney II announced Grimm as one of the candidates for the job. He was named as a finalist for the job along with Ken Whisenhunt and Mike Tomlin. On January 22, 2007, the Steelers hired Tomlin as their head coach. The day after Tomlin's hiring, Grimm was hired to serve under Whisenhunt as the Arizona Cardinals assistant head coach and offensive line coach.