Tim Duncan of the San Antonio Spurs turns 39 on Saturday, and the aging process for the best player on the best team of his generation has been gradually catching up with him. Coach Gregg Popovich says he believes Duncan will come back for another season, and that might be true, but it has become a popular theme among the national media to cover the Spurs during this postseason in the same way the Italian press chronicled the advance on Rome by the Visigoths.