HOUSTON -- The Houston Texans have ruled rookie quarterback C.J. Stroud out for Week 15 against the Tennessee Titans as Stroud is still in the concussion protocol.

Case Keenum, 35, will start in place of Stroud. Throughout the week Keenum and Davis Mills split reps, but coach DeMeco Ryans will roll with the 11-year veteran over Mills.

The last time Keenum started a game was in 2021, when he replaced Cleveland Browns quarterback Baker Mayfield for two games. Keenum threw three touchdowns with one interception and the Browns were 2-0 in those matchups.

Keenum hasn't been active in any game this season, as he has been in the emergency quarterback role. Mills has replaced Stroud whenever the rookie has left the game this season for a few snaps, and Mills finished the game against the Jets.

Stroud didn't practice all week, which indicated that the 2023 No. 2 pick didn't clear the five phrases of the protocol required to play against the Titans.

On Friday, Texans coach DeMeco Ryans said Stroud was "feeling better," but Stroud didn't recover enough to play this weekend.

It will be the first game Stroud misses in his career.

Stroud suffered a concussion when New York Jets defensive tackle Quinnen Williams delivered a blow in the fourth quarter of Sunday's 30-6 loss that knocked him out of the game in Week 14.