Josh Allen didn't complete many passes Sunday.

He completed a concussion evaluation in four minutes.

The Buffalo Bills quarterback passed the protocol tests and was medically cleared to return in the fourth quarter against the Houston Texans, head coach Sean McDermott reiterated Monday.

Allen is not in the NFL's concussion protocol.

"Josh was cleared and went back into the game," McDermott said. "That's what I know from our medical staff on the sideline."

Allen's head bounced off the ground when he was brought down on an incomplete pass in the 23-20 loss. Buffalo punted and Allen was sent to the medical tent for a concussion assessment. The Bills got the ball back four plays later after a strip sack and fumble recovery and Allen re-entered the game.

The Bills were criticized by fans and media for allowing Allen to continue playing and purportedly giving him smelling salts as he walked back onto the field.

"Josh is a warrior," coach Sean McDermott said in his postgame press conference. "Took a pretty good hit out there, and came back for his team and his teammates.”

The process of administering a multifaceted screen for a potential concussion takes at least 10 to 15 minutes, according to a consensus international statement by the Concussion in Sport Group. Allen was in and out of the medical tent in four minutes.

"Four minutes is going to be a pretty tight window," said Dr. Katie Rizzone, associate professor of orthopaedics at University of Rochester. "There are validation tests and questions. Asking about symptoms they're having would take a minute or two. Then you're going to put him through physical exam testing even if everything was negative and he felt OK. It's difficult but doable to examine a professional athlete in four minutes."

The CBS broadcast initially said Allen had a chest injury. Allen told reporters after the game he injured his chest and ankle on the play prior.

"Big shot to the chest. Rolled my ankle," Allen told reporters after the game. "They flagged me for hitting my head, but felt good enough to go back in."

Did Josh Allen suffer a concussion?

The Bills said no.

Concussions aren't always overt because they are based on science and symptoms and testing, Rizzone explained. There isn't a blood test or scan for diagnosis.

Neurologists look for headache, nausea and dizziness. They ask the patient orientation questions - where they are, what the score is - then more complex focus and concentration exercises like naming the months backward. A physical exam includes any abnormalities in pupils, eye movement and nerves around the neck and face. Athletes are put through balance testing like standing with their eyes closed or on one leg. Apps can detect how much someone is swaying when attempting to stand still.

Rizzone was surprised Allen came back in so quickly.

"That would be a pretty comprehensive exam to do on the sideline," said Rizzone, who is the team physician for University of Rochester and SUNY Brockport. "You could see initially he didn't feel right. But we don't know what happened in that tent. Adrenaline is a powerful drug and medical staff could've tested him quickly and he could've been normal on all those tests."

Reaction time is difficult to evaluate and one of the slowest baselines to return, Rizzone said. In football, a delay of couple of microseconds is significant.

It's unknown if Allen lost consciousness.

Allen could've evaded any head trauma on the impact. It's also possible Allen develops symptoms in the next couple of days and is required to enter the NFL concussion protocol.

How was Josh Allen injured?

The quarterback was dragged to the ground by the ankles by defensive end Mario Edwards Jr. as he threw the ball over linebacker Azeez Al-Shaair.

Allen's right buttocks, hip and shoulder hit the ground initially before the right side of his helmet ricocheted off the turf. His faceplanted before rolling onto his back. Both of Allen's arms bent 90 degrees at the elbows has he flexed his hands in the air and was tended to by medical personnel.

Allen told reporters an independent certified athletic trainer who serves as a spotter in the booth called for him to be checked for a concussion.

Allen was slow to get up the week prior against the Baltimore Ravens after receiving a forearm shiver from 338-pound defensive tackle Travis Jones. multiple blows on the same play. Allen went airborne and landed on his back as his head snapped back. Allen said after the loss that he aggravated his lower back hitting the ground but he'd be fine.

Josh Allen injury timeline: How long was he out of the game?

Allen missed one Bills offensive play and the entire process from injury to re-entering the game took six minutes of real time. It was four minutes from when he entered the medical tent until he jogged back on the field.

• 3:43 p.m.: Allen's head bounced off the turf while being brought down by Houston's Mario Edwards Jr. Allen threw an incomplete pass on the third-and-8 play and the Bills punted with 3:18 left in the fourth quarter.

• 3:44 p.m.: Allen walked to the bench under his own power and was surrounded by members of the Bills' staff

• 3:45 p.m.: He went into the medical tent with trainers and a neurotrauma consultant

• 3:49 p.m.: Buffalo's defense recovered a fumble, Allen was cleared to return, emerged from the medical tent, put his helmet on and returned to the game after missing one play.

Did the Bills give Josh Allen smelling salts?

Fox Sports 1 host and former NFL linebacker Emmanuel Acho posted a video with a screenshot of a Bills staff member appearing to hand Allen smelling salts.

"We all saw Josh Allen seemingly get knocked out, yet they just threw him a smelling salt and right back into the game," Acho said on X. "As if that was going to undo any head trauma he just suffered."

What are smelling salts?

Smelling salts are a mixture of ammonia and other chemicals that are inhaled to stimulate or restore consciousness. They can be used to help treat fainting. They have a strong bleachy cleaner smell.

The smelling salts irritate the inside of the nose and force deep breathing that clears out nasal passages and gives a boost of oxygen to the brain. They help the user feel more awake and alert with a kick of adrenaline and energy.

There is medical concern about using them for medical performance and counteracting the impact of head trauma.

"This can be dangerous as concussive symptoms could be masked, resulting in delayed diagnosis," according to Medical News Today. "Also, rapid return to the sport with a high risk of reinjury could worsen the consequences of head injury."

What were Josh Allen's stats after his injury?

Allen didn't complete a pass in five attempts after he returned to the game. He threw incomplete passes to James Cook and Curtis Samuel from the Texans' 15-yard line and the Bills kicked a field goal to even the game at 20-20.

Allen went 0-for-3 with three deep pass attempts on the Bills final possession, a stretch of three plays McDermott took the blame for after it gave the Texans time to get the ball back and kick a game-winning field goal.

Allen completed 9 of 30 passes - a career-worst 30% completion percentage - fort 131 yards.

NFL analysts call out league and Bills for letting Josh Allen return

Fans and analysts were shocked and upset Allen was allowed to return to the game.

NFL analyst and former quarterback Chase Daniel posted on X: "Uh oh looks like Josh Allen was unconscious after hitting his head on the tuff. If they let Josh Allen back into the game after he clearly smashed his head on the turf then the entire concussion process is flawed. He looked like he was out."

Dr. Chris Nowinski, a former WWE wrestler who is a neuroscientist and founder of the Concussion Legacy Foundation, posted on X: "It's insane that Josh Allen was put back in after this hit. Even if he says he's fine, why bet the franchise QB that concussion symptoms aren't delayed? Protocol aside, how are we taking risks like this just a few weeks after another Tua concussion?"

What is the NFL concussion protocol?

When a player receives an impact to the head during a game, the player goes into the Concussion Protocol if:

• The player exhibits or reports symptoms or signs suggestive of a concussion or stinger (a nerve pinch injury); or,

• The team athletic trainer, booth ATC spotter, team physician, NFL game official, coach, teammate, sideline unaffiliated neurotrauma consultant (UNC) or booth UNC initiates the protocol.

Then the player must be immediately removed to the sideline or stabilized on the field to undergo the concussion assessment, outlined in a concussion game day checklist, which can include a sideline survey, locker room exam and flow chart that determines if a player can or cannot return to play.

This article originally appeared on Rochester Democrat and Chronicle: Josh Allen injury: Should Bills QB have been allowed to return?