The NFL's concussion protocol appeared to fail Sunday when Texans quarterback Tom Savage took a huge hit, looked to have suffered a scary head injury, but was still allowed to re-enter the game. Ultimately, Savage headed back to the locker room where he was diagnosed with a concussion, but not before he returned to the field.

After getting slammed to the turf, Savage didn't get up immediately and his extended arms appeared to twitch for a few seconds. It was horrifying, even though it's impossible to know what exactly happened. The video below is not an easy watch:

An official stood directly over Savage and saw how he reacted to the hit, but Savage still returned to the game without missing an offensive play after he disappeared into the sideline medical tent for a quick evaluation, according the John McClain of the Houston Chronicle

Eventually, he headed to the locker room and handed over the offense to Texans backup quarterback T.J. Yates. The Texans then  ruled Savage out with a concussion. 

This isn't the first time this season that the NFL's concussion protocol has warranted criticism. In November, Colts quarterback Jacoby Brissett appeared to be woozy after a big hit, but still re-entered the game. The Colts placed him in the concussion protocol after the game. The team claimed that Brissett passed all concussion tests during the game and didn't show symptoms of a concussion until he was in the locker room following the game. 

The Colts' process was ripped by Dr. Chris Nowinski, the CEO of the Concussion Legacy Foundation, on Twitter.

Earlier in November, the officials sent Seahawks quarterback Russell Wilson to the sideline to get tested for a concussion, but Wilson appeared to bypass the test and immediately re-took the field.

Sunday's incident comes during a time when much of the dialogue surrounding the NFL has been centered around player safety. There was the recent incident of Patriots tight end Rob Gronkowski's cheap-shotting Bills' cornerback Tre'Davious White.

Steelers linebacker Ryan Shazier suffered a scary back injury on Monday night. And that same game featured a couple of gnarly headshots involving Steelers receiver JuJu Smith-Schuster and Bengals safety George Iloka

In 2015, a study found that 87 out of 91 deceased NFL players tested positive for CTE. In July, another study found that 110 of 111 former NFL players were diagnosed with CTE.

With all of the increased awareness surrounding concussions and head injuries, don't be surprised if the NFL investigates what happened on Sunday.