Brian Hoyer did suffer a concussion during Sunday night's 27-6 loss to New England.
"Brian Hoyer suffered a concussion near the end of the game and is in the concussion protocol as we speak," head coach Bill O'Brien said Monday.
Hoyer exited the game following a sack in the fourth quarter. His status for the Texans upcoming game at Indianapolis is "doubtful," according to O'Brien.
"It wasn't just a concussion," O'Brien said. "I think he strained his neck. He had a wrist problem. He took a beating last night. I think they were checking him out for all various injuries."
If Hoyer can't play in Sunday's matchup against the Colts, T.J. Yates will start.
"I am just going to prepare like I do every single week and just get ready to play if that needs to be," Yates said Monday. "I hope Brian is okay. I hope he is doing alright, but I'll be ready to play."
If he does, it will be Yates' second start of 2015. The fifth-year quarterback also started on Nov. 22 against the Jets, the last time Hoyer was in the concussion protocol. Yates was 16-of-34 for 229 yards, two touchdowns, no interceptions, and an 89.0 passer rating in the Week 11 win.
As a Texan, Yates played another important December game at Lucas Oil Stadium. On Dec. 22, 2011, Yates completed 13-of-16 for 132 yards and a 101.0 passer rating in the 19-16 loss to the Colts.
"Going up there before, played there before, started there, it's not a new territory that I have never been, but so many things are going to be different," Yates said. "The situation is still kind of the same for what's on the line. We have to go up there and win, that's the number one goal, that's the only thing that matters right now."
The (6-7) Texans will kick off against the (6-7) Colts on Sunday at noon CT. Both teams are vying for the AFC South division title with just three games remaining in the 2015 season.
Check out some of the best pregame shots from Sunday night's game against the Patriots.