After Tom Brady‘s wife, Gisele Bundchen, let it slip that he had played through a concussion last year that the New England Patriots never reported, the NFL has begun a review of the quarterback’s medical records.

They are looking to see if he either suffered a concussion or concussion symptoms. During his 17-year career, Brady has never been officially sidelined from a concussion, but his wife pointed out that he had been hurt from all the hits he’s taken.

Tom Brady played through a concussion last year on his way to a fifth Super Bowl title, according to his wife, supermodel Gisele Bundchen. The injury, which was not reported by the team, left her worried about how long he should continue to play football.

The NFL is taking a closer look at the Patriots’ injury reports and all reports about Brady filed by the brain injury specialists and spotters who worked at Patriots games last season.

“Football players playing through concussions is sort of the dirty little secret,” said Chris Nowinski, CEO of the Concussion Legacy Foundation. “In many situations, the player may not know they have a concussion. They may not recognize they have a concussion for another day or two.”

Last July, the NFL announced new protocols to evaluate and remove players with concussion symptoms. Teams that don’t comply can be fined hundreds of thousands of dollars and lose draft picks.

Brady said last May that football players should seek help for head injuries right away.

“You’d hate to stop doing something you love to do because of an injury. I’ve been very fortunate over the course of my career,” Brady said on ABC News in May 2016.

tom brady wife reveals concussion not reported by patriots

Asked if she wanted the New England Patriots quarterback to retire, Bundchen expressed concern “as a wife” in an interview on “CBS This Morning” that aired Wednesday.

“He had a concussion last year. He has concussions pretty much every …” she said, before cutting herself off. “I mean, we don’t talk about it. But he does have concussions. I don’t really think it’s a healthy thing for anybody to go through.”

Brady sat out the first four games of the season as punishment for his role in the “Deflategate” scandal and missed practice late in the season for leg, thigh and ankle injuries. But he was not listed on the league-required injury reports for a concussion or head injury at any point during either the 2016 calendar year or the 2016 season.

The NFL requires “significant or noteworthy” injuries to be reported, regardless of whether a player is expected to miss playing time, and says honest reporting of injuries “affects the integrity of the game.”

The Patriots and Brady’s agent declined to respond to Bundchen’s comments on Wednesday.

NFL spokesman Brian McCarthy said league officials reviewed all reports from independent neurotrauma consultants and athletic trainers who worked at Brady’s games during the 2016 season.

“There are no records that indicate that Mr. Brady suffered a head injury or concussion, or exhibited or complained of concussion symptoms,” McCarthy said. “Today we have been in contact with the NFLPA and will work together to gather more information from the club’s medical staff and Mr. Brady.”

The league is especially – though belatedly – sensitive to concussions, which have been linked to a brain disease that leaves former players forgetful, violent or suicidal. The NFL has agreed to pay $1 billion to retired players who accused the league of concealing the link between football and brain damage.

Chris Nowinski, a founder and the CEO of the Concussion Legacy Foundation, said only a small percentage of concussions are diagnosed, whether in the NFL or elsewhere.

“I’m most surprised that people think it’s really news that an NFL player had a concussion but it wasn’t diagnosed and it wasn’t reported,” he said Wednesday from the VA-sponsored Brain Trust conference at Harvard Medical School.

“But it is a great opportunity to educate people that it’s very dangerous to play through a concussion. And if you have an opportunity to get off the field and get it taken care of, you need to take it.”

By winning his fifth NFL title at the age of 39 – leading the biggest Super Bowl comeback in history – Brady has already defied age and cemented himself among the league’s all-time greats. He has long said he wanted to keep playing until his mid-40s, but he told ESPN in an interview published this week that he would continue beyond that if he was able to stay healthy and productive.

But Bundchen balked at those plans when asked by CBS host Charlie Rose about her husband’s plans.

“That kind of aggression all the time, that cannot be healthy for you,” she said. “I’m planning on him being healthy and do a lot of fun things when we’re like 100, I hope. I don’t really think it’s a healthy thing for your body to go through, like, you know, through that kind of aggression, like, all the time, that could not be healthy for you, right?”