One player who will be able to peacefully walk away is San Antonio Spurs power forward Tim Duncan. Duncan, almost unanimously regarded as the best power forward of all-time, has done just about everything a man can do in the game of basketball.
The mileage he has accumulated over the last 14 years have definitely caught up with him. It has been years since he has been healthy at the end of the year.
His knees and ankles require constant attention and treatment at this point. He plans on playing until the wheels fall off, but it is hard to imagine him being around past 2013. There is a chance he could decide this upcoming season is his last.