After starting the first 7 games of the 2008 season, Keasey was placed on injured reserve in week 8 with a torn biceps tendon. He was replaced in the 49ers starting lineup by all purpose back Michael Robinson.
In the first seven games of the 2008 season, Keasey was sidelined due to a torn biceps tendon and placed on injured reserve. His spot in the 49ers' starting lineup was taken over by Michael Robinson, who became the team's primary back.