There comes a time when all good things must end, and for these former NFL stars, if they haven't realized it yet, the time has come.
As an athlete, it is very hard to let go of the game you love because mentally that competitive spirit just never dies.
Unfortunately, the body doesn't have the same opinion.
So without further ado, here are four former NFL stars who just need to let go.
When Tiki Barber decided to come out of retirement, I'm not believing anything other than it was just a stupid publicity stunt.
No team is going to want him, and when the Giants won the Super Bowl the year after he retired, Barber felt left out.
So he tries to make a comeback, but has failed miserably.
Time to just give up, Tiki, because you're not getting any offers.
After the whole nasty situation with the Cincinnati Bengals, Carson Palmer should just be happy he's in one piece.
In the 2005 playoffs, he severely injured an ACL and was lucky to ever have the chance to play football again.
He should count his blessings that he can walk because the importance of health must enter the mind at some point.
This man made me cry when I was 10 years old, and I'll never forgive him for it.
It was the 1996 postseason, and my Denver Broncos were the No. 1 seed in the AFC.
In comes a second-year franchise, the Jacksonville Jaguars in the divisional round to Mile High Stadium.
Needless to say, I thought Denver had the win locked up.
Then Mark Brunell happened, and the world came crumbling down.
Since leaving Jacksonville, however, Brunell's been mainly a backup, so he should retire. Like right now.
He's the lesser-known version of Brett Favre and just needs to let go before he really gets hurt at his rightful age of 40.
Although Derrick Mason is most likely going to somewhat contribute to the Jets this season, he needs to hang it up.
Mason's a 37-year-old WR who's behind players with not only more talent, but youth.
He'll definitely regret not retiring once he gets leveled when he tries to make a catch across the middle.
Because he's not running deep anymore, those routes belong to Plaxico Burress and Santonio Holmes.
Be sure to check out John on Bleacher Report.
And you can follow him on Twitter @ Sportswriter27.