"Brandon [Weeden has] done a really good job," O'Brien said. "He did a good job in the Indy game, did a good job yesterday. But if Brian's healthy and cleared, he's our starter."
O'Brien said even if the Texans (8-7) clinch the AFC South on Monday night, rendering the Jaguars' game meaningless in terms of the playoffs, Hoyer will still start if cleared. If the Cincinnati Bengals beat the Denver Broncos on Monday Night Football, the Texans win the AFC South title. O'Brien indicated that he will not rest players against the Jaguars even if that happens.
"I think the most important thing is to win," O'Brien said. "I don't think there's any substitute for winning."
Hoyer's injury is part of a series of events that have caused the Texans to start four quarterbacks this season. Hoyer was the team's opening-day starter but was benched for Ryan Mallett. Hoyer regained the No. 1 role after Mallett went 1-3 in four starts, and the Texans released Mallett in the last week of October.
Hoyer played well until suffering a concussion against the Bengals on Nov. 16. Backup quarterback T.J. Yates entered the game and led the Texans to a 10-6 win.
That concussion caused Hoyer to miss the Texans' 24-17 win over the New York Jets. Hoyer returned the following week and started games against the Saints, Bills and Patriots. Against the Patriots on Dec. 13, Hoyer suffered his second concussion in less than a month. Yates started the following week against the Colts but suffered a torn ACL, requiring the Texans to turn to Weeden, whom they claimed off waivers Nov. 18.
Although Hoyer said he felt good on Thursday and traveled to Tennessee with the team, he had not cleared the league's concussion protocol.
In his absence, Weeden threw two touchdowns and ran for another, becoming the first quarterback in franchise history to do so. His 116.7 passer rating during the 34-6 win was the best of his career.
Texans outside linebacker Jadeveon Clowney is also recovering from a left foot injury suffered in the fourth quarter of Sunday's victory. Although Clowney initially reacted angrily to the injury, he later said he would be fine.
O'Brien said Clowney had no structural damage to his foot.
"You don't want to be not out there with the guys, so if you have a little nick or bruise, you'll be pissed off about it," Clowney said. "You just want to be out there with the guys and have fun and win games."