Deke didn't play any minute when Yao was healthy. That is too say, Yao actually had no substitute C,which may caused the tragedy for Yao. I'm not blaming Deke, but if AD doesn't want to use him as 2nd Center, We are not signing him for another season. We are grateful for what you did for us anyway, Deke.
Yao did have a replacement. It was Scola. It was Hayes. Yao didn't play every single minute of every single game this season. So are you saying we just never played with a 5 when he went to the bench? Yao's injury comes from the fact that he is a 300+ pound, 7'6 human being whose body has gone through a 20lb overhaul of pure muscle in a relatively short time span. Being THAT big and adding on even MORE muscle (or weight) wears down ligaments, bones, muscles, you name it. It has little to do with him playing a normal amount in an NBA game and more with the fact of his massive size. Doesn't that sound a little more logical?
Yao had substitutes, Carl and Luis played C occasionaly. Today's basketball has less and less real center like YAO, CAMBY, SHAQ, KAMAN, HOWARD etc. They're occasionaly power forwards.
Camby wasn't even really considered a "true" center when he entered the league back with the Raptors. He was played as a power forward with the Raps as well as the Knicks before Ewing went out. The fact that he is considered a traditional centre these days shows the changes in the trends in the last decade or so.