Horrible example, Strahan was a seasoned vet. He was a master of his craft. Peyton Manning won't play this pre-season and I believe missed all of camp. Now as long as he doesn't get out of shape, do I think he'll have a great season? Yes of course. This guy knows what he's doing.
Now could the same be said for Aaron Rodgers? No, he needs training camp and the pre-season. Does Brett Favre? Yes he's learning an entirely new system. If you have a hall of famer on your team, and just want him to stay in shape. Great, don't have him in camp or play them in pre-season. But chances are 85% of the roster needs it, if not more.