When Rodney Harrison played 15 seasons in the NFL as a defensive back, he gained a reputation for being a hard hitter and one of the most dangerous men in the league. Now a studio analyst for NBC’s Football Night In America, Harrison admits that years of hard hits are starting to take their toll on his health and likely will only get worse.

“I know it’s coming,” Harrison said during Thursday’s Dan Patrick Show. “Even now when I’m out on the golf course, there are times where I get these crucial migraines and this pounding of my head. Sometimes I get headaches to the point where I have to go lay down and get out of the sun. Sometimes, I do forget things.”

Earlier in the show, Patrick – a studio host for NBC Sports – interviewed former NFL quarterback Jim McMahon, who admitted that his short term memory is getting worse after years of taking hits to the head. McMahon, 53, also said that his girlfriend has had to take pictures of herself to make sure he remembers her.

“I’m 39 years old and this is something very scary to me at this point,” Harrison said. “I got a chance to sit with Jim McMahon in Tahoe for an hour … and he said ‘sometimes, I do forget things. Heck, I can’t remember what happened two or three days ago.’

“That’s scary to me because he was a quarterback, and I know that he got hit a lot, but I was a defensive back and I laid out and I used my helmet a lot. I got knocked out a lot.”

Harrison, a two-time All Pro who played for the San Diego Chargers and New England Patriots, was known for his big hits and reputation as a dirty player. During his career, he racked up over $300,000 in fines from the league and admits that he fears for some of the players that he hit during his career.

“I was trying to make a name for myself (early in his career),” Harrison said. “I was trying to establish that Rodney Harrison was not a just 5th round pick. I’m on of the best safeties around. How do you do that? You go out there and knock somebody out.

“I remember that I hit Jerry Rice with what I thought was a clean hit with my forearm right in his chest, and because of my reputation I get fined a $125,000 game check. And that’s because of my reputation. I had all the eyes in New York watching me.”

The NFL is currently facing a large class-action lawsuit from groups of retired players who felt that the league misled them about head injuries. Harrison, who was a teammate of the late Junior Seau with both the Chargers and Patriots, admitted that there were numerous occasions where he was sent back into games after being concussed, but also said that no one forced him to play the game.