Buckner (neck) was activated off the injured reserve list and will play in Monday night's matchup against the 49ers.
The 31-year-old opened the Colts' week of practice with consecutive full sessions and was originally listed as questionable for Monday night's contest. However, his questionable designation has since been removed, and he'll make his first appearance since the Week 9 loss to the Steelers. Now fully healthy, Buckner is expected to play as the Colts' top interior defensive lineman during the Week 16 matchup.