With the Pro Bowler gone, the Chiefs collapsed, getting outscored 19-0 in the second half of a 22-21 loss.
"A few things,'' quarterback Alex Smith said when asked after the defeat what changed for the Chiefs after a productive first half. "Obviously, [losing] Kelce hurts. A player of his caliber and not having him out there ...''
With 1 minute, 40 seconds left in the half, Kelce caught a 12-yard pass from Smith and took a hit to the helmet from Titans safety Johnathan Cyprien. Kelce needed help from his teammates to steady himself as he got up from the ground, but jogged off the field under his own power.
He was briefly examined by medical personnel on the sideline before leaving for the locker room. He later was ruled out for the remainder of the game.
Cyprien was not penalized for the hit.
Kelce had four catches for 66 yards, including a 13-yard touchdown, before departing. The Chiefs scored a touchdown on that drive to close the first half with a 21-3 lead.
But they were outscored 19-0 in the second half, collecting only 61 yards after their 264 in the first two quarters. Backup tight end Orson Charles dropped a third-down pass in the fourth quarter that would have allowed the Chiefs to convert.
"We've had guys step up and do [well],'' coach Andy Reid said. "We have a player down and I just expect the next guy to step up and go. That's how we've done it here and we've been successful with it. It didn't work out in our favor tonight.''