Team officials announced that Gaither signed his tender offer Wednesday.
The 26-year-old Gaither started the first three games of last season at middle linebacker, but was benched in favor of Jeremiah Trotter in Week 5. He suffered a season-ending foot injury the next week against the Raiders.
Gaither recorded 38 tackles and 1½ sacks last season. The former fifth-round pick has started 34 games at middle and outside linebacker since joining the team in 2006.