Indianapolis Colts stalwart offensive lineman Quenton Nelson was carted to the locker room after suffering an ankle injury in the first half of Sunday's game against the Tennessee Titans.
Ian Rapoport of NFL Network reported Nelson is believed to have a high-ankle sprain after being ruled out for the remainder of the contest. Rapoport noted X-rays were negative but that Nelson will undergo further testing.
Nelson's injury came early in the second quarter when his ankle rolled up during a run play. The Colts were dealt a blow early on when starting defensive end Kwity Paye was ruled out for the game after suffering a hamstring injury midway through the first quarter.
Nelson had dealt with a foot injury that required surgery in training camp. He announced that it was his third surgery of the offseason, but he was optimistic about his recovery. Indianapolis quarterback Carson Wentz suffered the same injury in camp. Both Nelson and Wentz recovered in time to play in Week 1.
The Colts also dealt with injuries to left tackle Eric Fisher and center Ryan Kelly during training camp.
When Nelson exited Sunday's game, he was replaced at left guard by Chris Reed. The Colts scored a touchdown on a nine-yard run by Nyheim Hines moments later.
Nelson is regarded as one of the best players in the NFL regardless of position, earning Pro Bowl and first-team All-Pro honors in each of his first three seasons in the league. He has never missed a regular-season start in his career.