Editor’s note: This story was originally published Sept. 13, following Miami’s loss to Buffalo. On Tuesday, a source confirmed to ESPN that the Dolphins are placing Tagovailoa on injured reserve.

MIAMI — After the Miami Dolphins‘ Tua Tagovailoa was diagnosed with the third concussion of his NFL career, a source told ESPN on Tuesday that the quarterback will be placed on injured reserve and be out for at least four games.

Tagovailoa was ruled out in the third quarter of the Dolphins’ 31-10 loss to the Buffalo Bills on Thursday after a play in which he scrambled up the middle for a first down and lowered his shoulder to initiate contact with Bills safety Damar Hamlin. After Tagovailoa’s helmet made contact with Hamlin’s body, the quarterback fell to the ground and went into a fencing response, a term used to describe a person’s arms going into an unnatural position.

Dolphins medical trainers attended to Tagovailoa for several minutes as players knelt around him. He was ultimately able to walk off the field and into the team’s locker room under his own power.

From that point, Dolphins had 10 days until their next game against the Seattle Seahawks to rule out Tagovailoa, regardless of how he progresses through the league’s concussion protocol. They ultimately placed him on IR.

He is not guaranteed to return when Miami hosts the Arizona Cardinals in Week 8. The team is not rushing its recently crowned franchise quarterback back from another traumatic head injury. Tagovailoa will seek opinions from multiple independent neurologists before returning to the field.

When asked about Tagovailoa’s future in football, Dolphins coach Mike McDaniel said it was up to the quarterback to decide.

“As far as Tua’s career is concerned, I think it’s of utmost priority of mind for Tua to speak on Tua’s career,” McDaniel said. “So I think reports are reports. As far as I’m concerned, I’m just worried about the human being and where that’s at day to day, and I think I’ll let Tua be the champion of his own career and speak on that.”

This is the first time Miami has been forced to play without its starting quarterback since 2022, when Skylar Thompson and Teddy Bridgewater started a combined five games, including a playoff loss to the Bills. Since Tagovailoa entered the league in 2020, the Miami is 33-20 in games he started and 7-9 in those all other QBs started, including Thompson, Bridgewater, Jacoby Brissett and Ryan Fitzpatrick.

According to ESPN Research, the Dolphins have a 19% chance to make the playoffs, which ranks 13th out of 16 AFC teams. Miami has a 3% chance to win the AFC East.

Here’s what we know about Tagovailoa’s situation:

What is Tagovailoa’s injury history?

Tagovailoa was a candidate to be selected as the top quarterback in the 2020 NFL draft during his final season at Alabama but suffered a hip dislocation and fracture of the posterior wall of his hip socket midway through the season. He was also diagnosed with a concussion and broken nose that year.

Tagovailoa recovered in time to play for the Dolphins as a rookie but missed five games during his first two seasons because of various minor injuries. In 2022, he was diagnosed with two concussions and took a third hit to his head that ultimately led to the NFL altering its concussion protocol.

He didn’t miss a game during the 2023 season, however, and earned a four-year, $212.1 million contract extension in July.

What options did Tagovailoa consider after his 2022 season?

Tagovailoa admitted to briefly considering retirement after conversations with his family. During an interview with “The Dan Le Batard Show” last month, he clarified that it was primarily his mother who asked him to reconsider his playing career.

Ultimately, he decided against it and spent the 2023 offseason bulking up and training in a jiujitsu breakfall program to learn how to fall without hitting his head on the ground.

Tagovailoa also began wearing a VICIS helmet specifically designed to limit concussions for the wearer.

“It was like a percentage better than the helmet that I had,” Tagovailoa said in August 2023. “Everything matters and so I’m going to play that percentage. So if you look at it last year, it wasn’t anyone really hitting my head. It was really just the ground.”

The training and helmet change seemed to help as he played in all of Miami’s games last season, including a playoff loss to the Kansas City Chiefs. This offseason, Tagovailoa told CBS Sports he lost 14 pounds in an effort to be more mobile.

If Tagovailoa wants to return to the field, what hurdles will he have to clear in concussion protocol?

McDaniel said Tagovailoa will undergo thorough testing and evaluation. The NFL’s return-to-participation protocol is a five-step process that culminates in a team’s physician concurring with an independent neurological consultant that a player can safely play again.

The first step of the protocol is rest and recovery “until his signs and symptoms and neurologic examination” return to “baseline status.” The next step is light aerobic exercise, followed by continued aerobic exercise and introduction of strength training.

A player can return to football activities in the fourth step of the protocol, all of which are noncontact. The final step is full clearance, once the physician and neurological consultant agree the player is ready.

What are the Dolphins’ options at quarterback? Will they sign another player?

Third-year quarterback Skylar Thompson is in line to start. Thompson started three games as a rookie in 2022, including a playoff loss on the road at Buffalo. On Monday, the Dolphins signed quarterback Tyler Huntley to be the backup. McDaniel said the move to add Huntley “was not any direct reflection on Skylar” and was made to bolster the team’s depth.

The other quarterback on the roster is Tim Boyle, who is signed to the practice squad.

McDaniel expressed the “utmost confidence” in Thompson, who beat out veteran Mike White for the backup job this offseason — in part because of how the coach said the team responded whenever Thompson was on the field.

Sunday will mark his second-ever road start. Dolphins linebacker Jordyn Brooks, who played for the Seahawks for four seasons, said his advice to Thompson for Sunday’s game is to remember that his teammates are on the field with him, to trust in this week’s preparation and to just play his game.