Tua Tagovailoa has not been cleared to return ahead of the NFL playoffs, leaving Miami Dolphins rookie Skylar Thompson to start again at quarterback against the Buffalo Bills.

A promising season for Tagovailoa and the Dolphins has been rocked by repeated concussion concerns.

Tagovailoa hit his head against the ground twice in the same week in September, but only the second incident was logged as a concussion as he left a defeat to the Cincinnati Bengals. The first hit, against the Bills in Week 3, was described as a back issue.

The former Alabama QB missed two games then before returning, only to suffer another concussion against the Green Bay Packers on Christmas Day – one that was not identified until the following day.

Tagovailoa has not played since and will not line up against the Bills in this week's Wild Card round matchup.

Coach Mike McDaniel confirmed Tagovailoa was out, while the Dolphins are now preparing for Thompson to start as Teddy Bridgewater also remains sidelined after dislocating a finger.

Thompson's first NFL start was in Week 6, with Tagovailoa still out and backup Bridgewater also dealing with a concussion. The rookie left the game with a thumb injury.

He had to wait until Week 18 for both Tagovailoa and Bridgewater to be out again ahead of a crucial meeting with the New York Jets.

After five straight defeats, Thompson helped the Dolphins edge to a narrow 11-6 win that booked their place in the postseason, teeing up another meeting with AFC East rivals the Bills, against whom the seventh-round pick is again set to start.

Miami Dolphins quarterback Tua Tagovailoa will miss another game due to concussion, confirmed head coach Mike McDaniel.

Tagovailoa was highly unlikely to feature in Sunday's game against Minnesota Vikings despite returning to the practice field this week, but McDaniel declared he would not play on Wednesday.

The Dolphins QB has not played since being concussed in the Week 4 game against the Cincinnati Bengals on September 29.

Tagovailoa's replacement, Teddy Bridgewater, was also concussed in their Week 5 game against the New York Jets, meaning rookie quarterback Skylar Thompson will make his first career start versus the Vikings.

"Now, when talking about this week and playing, I don't see a scenario - I don't see him being active. I do not plan to have him play at all," McDaniel told reporters about Tagovailoa.

"As far as his exact timeline of when he's going to play, I'll be excited to consider that whenever that comes up. Right now, I'm just really focused on him getting out there and feeling good and being around his teammates, and that those types of decisions aren't in the immediate future right now. I'll handle that when that comes after."

McDanel revealed Tagovailoa may pass concussion protocol the Week 6 game but that the Dolphins would not rush him back despite being depleted in that department with Bridgewater out.

"He hasn't done a thing on the football field for literally two weeks," McDaniel said.

"I don't think that that would be fair to the player. That wouldn't be fair to the team… I don't feel comfortable putting him in that situation."

Tagovailoa was stretchered off and briefly hospitalized after hitting his head on the turf and being concussed against the Bengals.

That came only four days after a similar incident against the Buffalo Bills where he was evaluated for concussion at halftime, having appeared unstable on his feet but cleared to play on.

The incident led to the NFL Players' Association conducting a review of the league's concussion protocol, which was amended last week to include ataxia as a symptom. Bridgewater was the first player impacted by the protocol change in Week 5.

The Dolphins are on a two-game losing streak, sitting 3-2 after beginning the 2022 season with three successive wins.

The Miami Dolphins' winning start to the season is over and quarterback Tua Tagovailoa was stretchered off in a scary incident during their 27-15 loss to the Cincinnati Bengals on Thursday.

Joe Burrow threw two touchdown passes for the Bengals who claimed back-to-back wins to improve to 2-2, but the game will be remembered for Tagovailoa's injury where he was stretchered off and rushed to hospital with "head and neck injuries".

Tagovailoa went down during an eventful second quarter, slamming the back of his head into the turf in a Josh Tupou sack, where he appeared to suffer a seizure upon the initial contact. The Dolphins QB copped a heavy hit in last week's win over the Buffalo Bills but cleared protocols to play on despite fears of a concussion.

Teddy Bridgewater stepped in for Tagovailoa, shoveling a pass for Chase Edmonds' touchdown on half-time to reduce the margin to 14-12 at half-time.

Jason Sanders converted his third field-goal attempt of the game to have Miami up 15-14 at the final change, but the Bengals did all the scoring in the fourth quarter with Evan McPherson slotting two field goals before Burrow found a wide-open Hayden Hurst for a late TD after Vonn Bell's second interception.

Earlier, Bengals running back Joe Mixon opened the scoring, before both sides traded touchdowns in the second quarter, with Burrow connecting with Tee Higgins for a 59-yard TD deep down the left side.

Burrow completed 20 of 31 attempts for 287 yards and two touchdowns with no interceptions, while Mixon had 24 carries for 61 yards. Higgins starred with 124 yards from seven receptions and Ja'Marr Chase made 81 from four receptions, including a Tyler Boyd 23-yard pass.

Tagovailoa made eight of 14 passes for 110 yards with one interception before being taken off, with Bridgewater completing 14 of 23 passes for 193 yards with one TD and an interception after stepping in. Wide receiver Tyreek Hill had 160 yards on 10 receptions.

Tua Tagovailoa has been formally listed as "questionable" for the Miami Dolphins' Thursday night game against the Cincinnati Bengals.

Suffering with back and ankle problems, Tagovailoa has only been able to play a limited part in preparation this week.

Dolphins coach Mike McDaniel asserted on Monday it was the 24-year-old Tagovailoa's injured back that caused him to stumble to the ground in Sunday's 21-19 win over the Buffalo Bills, amid fears of a concussion.

Tagovailoa took a hard hit in that game, as Bills linebacker Matt Milano pushed him to the ground. Tagovailoa's helmet slammed into the turf, but he rose to his feet quickly. However, he then shook his head, appeared woozy and lost balance as he stumbled back to the ground.

The 24-year-old quarterback went to the locker room to be assessed by the team's medical staff, with the Dolphins announcing a head injury.

He returned for the start of the third quarter – a move that prompted the NFL and National Football League Players Association to conduct a joint review of how the decision was made to allow Tagovailoa to return.

McDaniel maintained, however, that proper protocols were followed and Tagovailoa was cleared by the team and the independent neurologist.

Tagovailoa said after the game that it felt like he hyper-extended his back earlier in the contest, which was why his back locked up on him after the hit from Milano, causing the stumble.

The Dolphins have Teddy Bridgewater on standby to start on Thursday.

McDaniel was hoping to make a decision on Wednesday about his starting quarterback, but said it might have to come down to an early call on Thursday instead, stressing he would back 29-year-old Bridgewater to come good if called upon.

"We have a bunch of faith in him. So we're walking through in general, anyway," McDaniel said on Tuesday. "So Teddy has to take reps each and every play in terms of calling the play and visualising everything as it stands.

"We'll probably just take it as long as we have to before we can be convicted. But at some point there has to be [a decision] – it won't be five minutes before kick-off, I know that. Probably some time on Wednesday, but if we have to, we'll move it to Thursday morning."

The Miami Dolphins have agreed to a one-year contract with quarterback Teddy Bridgewater, likely adding an experienced backup behind 2020 fifth overall draft pick Tua Tagovailoa.

The sides can finalise the deal on Wednesday when the NFL's free agency period begins. Monday marked the beginning of the league's legal negotiating period.

Bridgewater, 29, is a South Florida native who had a decorated career at Miami Northwestern Senior High School and has returned to his alma mater frequently to watch Friday night games.

While Tagovailoa is expected to remain the Dolphins' starter, he has dealt with several injuries in his first two pro seasons, making the acquisition of a reliable quarterback a priority for Miami.

The 32nd overall pick in 2014 out of Louisville, Bridgewater will once again be relegated to a backup role after starting 29 games over the last two seasons for the Carolina Panthers and Denver Broncos.

In 14 games last season, he threw for a career-high 18 touchdown passes for the 7-10 Broncos, who revamped the position last week by agreeing to a blockbuster deal with the Seattle Seahawks to acquire Russell Wilson.

With Bridgewater set to be signed and Mitchell Trubisky agreeing to a deal with the Pittsburgh Steelers, the offseason quarterback carousel is beginning to settle, with Jameis Winston and Marcus Mariota remaining the top two available free agents.

The elephant in the room for teams acquiring quarterbacks remains the status of Deshaun Watson, who has requested a trade from the Houston Texans despite having 22 civil lawsuits against him for allegations of sexual harassment and sexual assault, which he denies. A grand jury deemed there insufficient evidence for criminal proceedings last week.

The Dolphins and Texans were deep into conversations about sending Watson to Miami before last year's trade deadline, but no deal was made.