Before former NFL player Bob Probert died of heart failure at the age of 45 last July, he decided to donate his brain to science.
According to reports, Boston University scientist say Probert suffered from degenerative brain disease called chronic traumatic ecephalopathy.
Brain injuries are being studied more than ever before due to injuries football players and hockey players have suffered throughout there careers. Leagues, all the way down to high school, have developed stricter rules when it comes to concussions.
Probert, who played for the Detroit Red Wings and the Chicago Blackhawks was known as one of the leagues most feared enforcers.
Although the NHL has taken steps to reduce head injuries, fighting is still a big part of the game.