Although Texans quarterback Tom Savage is improving, he remains under the NFL concussion protocol and is unavailable for a Sunday road game against the Jacksonville Jaguars.

Savage suffered a major concussion Sunday when he was blasted by San Francisco 49ers outside linebacker Elvis Dumervil. The handling of his injury and him being allowed to go back into the game initially before later being ruled out is the subject of an NFL-NFL Players Association joint investigation.

"I talked to him a few times, a couple times," Texans coach Bill O'Brien. "Seems like he's doing well. He's in the protocol and he's just kind of going through that right now."

O'Brien said that Savage hasn't been ruled out for a Christmas game next week against the Pittsburgh Steelers.

"There's always a chance for those things, yeah," he said.

T.J. Yates will start with Savage out. The Texans are planning to promote Taylor Heinicke from the practice squad to be the backup.

"Taylor Heinicke will be the backup, more than likely," O'Brien said. "We haven't made that roster move yet but that's the way we're leaning right now."

O'Brien declined to say who would be his emergency quarterback. Braxton Miller is under the NFL concussion protocol.

"I don't want to get into that," O'Brien said. "I have one or two or three, but you can find that out on gameday."