INDIANAPOLIS -- Colts All-Pro linebacker Shaquille Leonard, making his season debut after back surgery, was ruled out of Sunday's game against the Tennessee Titans after suffering a concussion in the second quarter.
Leonard was injured in a collision with teammate Zaire Franklin when the two players converged on tight end Chig Okonkwo, with Leonard taking a shot to the head in the process. Leonard went down and remained on the ground for a few moments before being helped to his feet and taken immediately to the locker room. He appeared to be holding a towel over his face as he left the field, perhaps suggesting a facial injury.
Leonard had been recovering from back surgery since June and finally returned to the lineup Sunday after making steady progress in recent weeks.
He finished the game with two tackles in the 24-17 loss.
Leonard's injury comes ahead of a short week for the Colts. Indianapolis plays at Denver on Thursday night, giving Leonard less time to clear the concussion protocol before the team's Week 5 game.