One of the most legendary figures in NFL history will deliver a sobering message to football fans on the morning of Super Bowl XLVIII. Former New York Jets quarterback Joe Namath, who famously guaranteed a win for his underdog squad in Super Bowl III, revealed the toll that football has taken on him in an interview with CBS scheduled to air on Sunday.

"I've been through some things medically. I've seen some things on my brain," Namath told Rita Braver of CBS Sunday Morning in a brief preview of the interview released in advance. "But I've had treatment, and I've improved. None of the body was designed to play football. Excuse me, you know, football, we're just not designed for it."

Namath, 70, played 13 seasons in the NFL after starring at the University of Alabama. He was drafted by the Jets in the 1965 AFL Draft with the No. 1 overall selection. Dubbed "Broadway Joe," Namath quickly emerged as a star on and off the gridiron. In his fourth season, Namath piloted the Jets to an upset triumph over the Baltimore Colts in the third edition of the Super Bowl. Although his career would be plagued by injuries, he would be elected to the Pro Football Hall Of Fame in 1985.

With Super Bowl XLVIII being played in the home stadium of his former team, Namath has been one of many familiar faces in New York City ahead of the game between the Denver Broncos and Seattle Seahawks. Amid the celebratory clamor on both sides of the Hudson River, Namath has been making startling revelations about possible brain damage he has suffered.

"I was thinking I have grandchildren, I have daughters. It behooved me to find out what was going on," Namath told CNN's Piers Morgan in an interview that aired on Friday. "I didn't have any symptoms to speak of but I did go get investigated, get looked at, get analyzed, took some treatment. Yes, there were areas in my brain that the cells had ceased, quieted down tremendously and we were concerned a bit. So I have had some treatment and I feel great."

Namath told Morgan that he decided to have himself examined after hearing so much about the long-term health risks increasingly associated with football. During his visit with the CNN host, Namath recalled the cavalier response to in-game head injuries during his era.

"I can count the times that I had situations where I hit the ground, hit in the head, lose it, you don't know for a while," Namath said. "We used to call it 'getting your bell rung.' And then whenever you took some time, maybe a little oxygen, you went back to work."

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WATCH: Joe Namath Talks With Piers Morgan

Namath insisted to Morgan that he had been "feeling pretty good" before being examined but many of his colleagues are not so lucky. Pro Football Hall of Fame running back Tony Dorsett revealed his cognitive struggles to ESPN in November 2013 after researchers at UCLA told him that he showed signs of chronic traumatic encephalopathy (CTE), a degenerative brain disease some scientists believe may be triggered by the repetitive head trauma suffered by football players.

"My quality of living has changed drastically and it deteriorates every day," Dorsett told ESPN.

Dorsett, 59, entered the league in Namath's final season, 1977. He spent 12 seasons in the NFL, 11 with the Dallas Cowboys. He retired after the 1988 season and was inducted into the Hall of Fame in 1994. Twenty years later, he struggles with his memory and emotions.

“Remembering people’s names; I take my kids to practice for years, and all of a sudden, I don’t know how to get there,” Dorsett told CBS Pittsburgh in November. “Those kinds of things, it’s very frustrating. It makes me mad; it’s just a real frustrating thing I’m going through, but again, I’m trying to be proactive rather than inactive and trying to cut it off.”

The winner of the 1976 Heisman Trophy while playing at the University of Pittsburgh, Dorsett was among the more than 4,500 former players who sued the NFL, alleging the league concealed long-term dangers of concussions and rushed players back into action after suffering head injuries. A proposed $765 million settlement between the NFL and the plaintiffs in the case has been put on hold. U.S. District Judge Anita B. Brody denied preliminary approval for the settlement, citing fears that there may not be enough funding to cover 20,000 retired players.