Tagovailoa (1) reacts with wide receiver Jaylen Waddle after running for a first down against the New England Patriots.
CNN  — 

The Miami Dolphins officially exercised quarterback Tua Tagovailoa’s fifth-year option on his rookie contract on Monday.

The 24-year-old is now contracted with the team through the 2024 season. He will be guaranteed $23.2 million for the 2024 season, according to the NFL.

Tagovailoa was the NFL’s highest-rated passer last season with a 105.5 rating, becoming the youngest player to lead the league in passer rating since former Dolphins quarterback Dan Marino did so in 1984.

However, despite showing flashes of the promise the Dolphins saw in him coming out of Alabama, Tagovailoa had a tumultuous season last year, particularly down to his battles with head injuries.

Tagovailoa suffered three concussions throughout the year, raising scrutiny about the NFL’s concussion protocols.

His health scares started September 25 in a game against the Buffalo Bills, when Tagovailoa stumbled backward and fell during a play, hitting his head on the turf. Though he initially stood up on his own, Tagovailoa then staggered and had to be helped by two teammates.

Tagovailoa was taken out of the game, evaluated by doctors and allowed to return after halftime. Later, both the NFL and the NFL Players Association concluded that concussion protocols were correctly followed.

But four days later, in a game against the Cincinnati Bengals, Tagovailoa was injured again in a scary looking incident, carted off the field and taken via ambulance to a nearby hospital. This time, he was diagnosed with a concussion. Days later, the NFLPA fired the unaffiliated neurotrauma consultant involved in the decision to let Tagovailoa return in the game against the Bills.

Tua Tagovailoa looks on from the field during the Dolphins' game against the Green Bay Packers at Hard Rock Stadium.

On Christmas against the Green Bay Packers, it happened again. This time, Tagovailoa was not evaluated during the game – the diagnosis came the next day after he showed concussion-like symptoms. The Dolphins shut Tagovailoa down for the rest of the season, meaning he missed the Dolphins’ playoffs game against the Bills. Two concussions occurring close together can have permanently disabling effects, according to the American Association of Neurological Surgeons.

Players sustained 149 concussions in games this season – an 18% increase over 2021, the NFL said last week. That total also is 14% higher than the three-year average (130) between 2018 and 2020.

The league’s chief medical officer attributed the rise in part to a protocol change that he said “broadened and strengthened” the definition of a concussion following Tagovailoa’s injuries earlier in the season.

Tagovailoa was the fifth overall pick in the 2020 NFL draft out of Alabama. He has played in 36 career games with 34 starts, completing 708-of-1,078 career passes for 8,015 yards and 52 touchdowns.

In 2022, Tagovailoa was voted a team captain and won the Don Shula Leadership Award, selected by his teammates.

CNN’s Leah Asmelash contributed to this report.