Sam Shields on the field during a game against the Chicago Bears at Soldier Field on September 13, 2015.
CNN  — 

Former Green Bay Packers cornerback Sam Shields has said he regrets playing in the NFL, pointing to the effects concussions and head injuries had on his career and his later life.

Having played seven seasons with the Packers, Shields missed almost 14 months with concussions between 2016 and 2017, returning to the field for one final season in 2018 with the Los Angeles Rams before retiring.

But, in a frank interview with Dan Le Batard in the ‘South Beach Sessions’ podcast, the 34-year-old Shields described his head being “all mushed together with the concussions.”

He added that he still suffers with headaches, a lack of appetite and sleep issues as a result of the concussions – and the cutthroat nature of the NFL.

“Once you’re in that NFL, 100% of the responsibility’s on you. So you got to take risks because you got to take care of your family,” said Shields.

“When you’re done with football, everybody forgets about you. Family, friends. I have one friend. In football, I had 10.

“Right now, I’ve I got one where I know that that’s my friend. That I could really say: ‘You’re my friend.’ I don’t even talk to most of my family members. Once football was over, everybody was over with me.”

In a Players Tribune article that Shields wrote in 2018, he outlined some of the symptoms he experienced, which attributed to the concussions he suffered.

“It was three o’clock in the morning on some night in January 2017,” he wrote. “I forget which one. I’d had a lot of bad nights around that time, but this one was the worst.

“I couldn’t sleep. It felt like my brain was cramping, or like it was trying to break out of my skull or something.

“I was rolling around in my bed, whipping my body back and forth, trying to escape the pounding inside my head. Next thing I know, I’m curled up in the fetal position, shaking and crying.”

Shields outlined that he was out unavailable to play while with the Packers for almost two years due to being in the concussion protocol.

And he questioned the support he received from the organization in rehabilitating him with his head injuries.

“They didn’t really put much effort into checking to see if this dude is alright. They just wondered: ‘Is Sam going to play this week? He’s not playing? Oh, he’s got to go.”

The Packers didn’t immediately respond to CNN’s request for comment.

Shields describes receiving help from doctors at UCLA after wondering why his head was all “blurry.”

It is only after taking time off and seeking help himself that he began to rehabilitate from his concussions and “beat them.”

Shields is helped off of the field after taking a hit in the second quarter of the game against the Dallas Cowboys at Lambeau Field on December 13, 2015.

Shield also attributes his issues with his head injuries being the reason for firing his agent, Drew Rosenhaus.

“It was always: ‘Sam, you can do this. The money.’ I ain’t give a damn about no money. I just wanted to get my head right. My s**t is not together. … I felt like he wasn’t supportive of my health. In the two to three years I was out the league, I didn’t hear from Drew.”

Rosenhaus didn’t immediately respond to CNN’s request for comment.

When asked by Le Batard whether, if given the chance to redo his life, he would choose to play in the NFL again, Shields was unequivocal.

“No,” Shields said. “I’d be going to school, trying to work for home improvement. I’d be trying to learn how to build a house.”

The NFL revamped its concussion protocols this season after Miami Dolphins quarterback Tua Tagovailoa’s injury on September 25.

Tagovailoa suffered an apparent head injury and was later allowed to reenter the game. Tagovailoa, 24, was later hospitalized for a concussion.

The National Football League uses ATC spotters, who are independent certified athletic trainers, to monitor all games.

The spotters “serve as another set of eyes, watching for possible injuries at every NFL game,” according to NFL Football Operations.

For example, stumbling is a considered a sign of ataxia as it demonstrates impaired motor function. The league defines ataxia as “abnormality of balance/stability, motor coordination or dysfunctional speech caused by a neurological issue.”

The protocol modification announced by the NFL and NFL Player’s Association said a player showing signs of ataxia while being evaluated for a concussion would be prohibited from returning to the game.

Why are concussions important in the NFL?

Concussions and their prevention have become an important issue in recent years due to their connection to brain disease later in life.

In 2017, a study published in the medical journal JAMA (Journal of the American Medical Association) found that chronic traumatic encephalopathy, known as CTE, was found in 99% of deceased NFL players’ brains that were donated to scientific research.

The neurodegenerative brain disease can be found in individuals who have been exposed to repeated head trauma.

The disease is pathologically marked by a buildup of abnormal tau protein in the brain that can disable neuropathways and lead to a variety of clinical symptoms.

These include memory loss, confusion, impaired judgment, aggression, depression, anxiety, impulse control issues and sometimes suicidal behavior.

It can only be formally diagnosed with an autopsy, and most cases, although not all, have been seen in either veterans or people who played contact sports, particularly American football.

A 2018 study found that CTE can start early and without any signs of concussion.

Dr. Lee Goldstein, one of the authors on the study published in the journal Brain, and his colleagues from Boston University evaluated the brains of four deceased athletes, ages 17 and 18 years old.

All four had died within a day to four months of receiving some sort of sport-related head injury and had a history of playing football.

Earlier this year, former NFL player Demaryius Thomas died suddenly at the age of 33. Months after, Thomas’ family said he had been suffering from stage 2 CTE when he died.

Also in recent years, Vincent Jackson, who died aged 38, and Phillip Adams – who fatally shot six people before taking his own life – were both posthumously diagnosed with CTE.

A study in 2021 also found that NFL players are about four times more likely to die of amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, than the general public.

ALS is a neurodegenerative disease more likely to be diagnosed in older White men. The root causes are still unknown, and most cases are considered sporadic.

The researchers hypothesized about a relationship between head trauma and ALS because of a similar link detected between football and the neurodegenerative disease CTE. Previous research has noted that CTE and ALS may have some similar impacts on the brain.