Nelson had his lower leg rolled up on a running play. The guard remained on the ground momentarily before getting up and walking off the field on his own very gingerly. The Colts' training staff tended to Nelson on the sideline before he ended up being carted to the locker room.
Nelson later returned to the sideline with his right ankle heavily wrapped. Chris Reed replaced Nelson, who has not missed a game since entering the NFL as the No. 6 draft pick in 2018.
Nelson, an All-Pro in each of his first three seasons, has been battling injuries all season. He missed three weeks of training camp after having right foot surgery in early August. He has been dealing with a back injury since the start of the regular season.
Colts defensive end Kwity Paye also was ruled out after suffering a hamstring injury.