 The Atlanta Falcons' new head coach, Mike Smith, named Grimes a starting cornerback to begin the 2008 regular season, along with Chris Houston.He made his first career start in the Atlanta Falcons' season-opener against the Washington Redskins and recorded a season-high six solo tackles in their 34–21 victory.On September 21, 2008, Grimes made one tackle, two pass deflections, and made his first career interception off a pass by quarterback Tyler Thigpen during a 38–14 win against the Kansas City Chiefs in Week 3.