joining us is sports expert mary pillan. and lay out the science. is this a logical decision based on what we know about sports injures in the nfl? >> absolutely. i think this is what they've been writing about for years. this is what we are learning. but this is not good. the civil suit against the league comes to mind as a great example of players looking at the brain scans that we didn't have in past and looking at their own careers and i think that players like borland in the middle or start of their promising pro careers are looking at the junior seaus and younger players will say i don't know if this is what i'm signing up for when i fell in love for the game. >> and some are saying that him retiring is what the nfl should be terrified about. don't be fooled. it is not the end of pro football but it might be the beginning of the beginning of the end, especially as the nfl's major popular sport. >> it might by' trend. and boxing coming up as a trend. when you read boxing in the 30s and 40s is different than what it is. and there is tv money pum