Texans head coach Bill O'Brien said Savage was checked immediately after the hit, but was cleared by the unaffiliated neurotrauma consultant to return to the game. After the following series, Savage was tested again and it was determined he needed to leave the game.
"[They] made the determination that he was OK," O'Brien said. "Not me, obviously the evaluators made the determination to put him back in the game. He went back in the game and came out and they evaluated him a little bit more just because of what they saw."
"Whatever [the evaluators] see and the testing that they do they try to make the best decision with the player and they weren't satisfied with the results of the second test so they decided to pull him, and that's when he went into the locker room."
Savage was hit by 49ers defensive end Elvis Dumervil while throwing an incomplete pass on third down. He appeared to have trouble getting up and seemed dazed, and his hands were visibly shaking.
Savage was checked out in the medical tent for less than three minutes, then returned to the game for one series and threw two incomplete passes. He went to the locker room with two minutes remaining in the half and was replaced by T.J. Yates.
After taking the hit, Savage spent time talking to the team's medical staff. Before the Texans' next offensive series, a team official held on to Savage's jersey and arm as he tried to go on to the field. Savage could be seen arguing with the team official before he was escorted to the locker room by the team's trainer.
That Savage was allowed back on the field at all drew the ire of Chris Nowinski, the founding CEO of the Concussion Legacy Foundation and co-director of Boston University's Center for the Study of Traumatic Encephalopathy.
On his first series, Yates led the Texans on a nine-play, 75-yard touchdown drive, throwing a 7-yard pass to wide receiver DeAndre Hopkins.
He threw for another touchdown in the 26-16 loss and finished 14-of-26 for 175 yards.
The Associated Press contributed to this report.
Savage returns to game after massive hit on sack
Tom Savage appears to be shaken up after taking a hard hit in the end zone. Savage goes through concussion protocol and returns for a series, but is later replaced by T.J. Yates.
O'Brien explains why Savage left the game
Texans head coach Bill O'Brien says that he leaves medical decisions in the hands of the team trainer and doctor and in QB Tom Savage's case, the pair wasn't satisfied with the outcome of their second round of testing.