Lots of folks are being too harsh on the player, which is not very surprising.
Just a couple months ago some of the same people praised the lad for his performance against Inter where he was everywhere and didn't let a single man through. His tackling, along with his speed, stopped several attacks from a few of the best players in the league. The tackle on Milito in the box was quality. But of course, now that he has another boneheaded game, the cats out of the hat and he isn't worth the time anymore.
You can't be a horrible player to shut down the likes of Milito and Sneijder. Clearly the guy has a tendency to make very poor decisions while defending, especially in situations where he does have support behind him. Caceres did the same thing in the playoff against Argentina -- needless tackle when he thought he was the last man but was not, yet still got the red. It's not that he's poor in reading the game apart from reading when to dive in, something that takes practice and patience.
So if he can be taught not to recklessly dive in all the time and contain a bit more, improving his timing and overall decision-making, he won't be a bad defender. Caceres has the agility and athleticism to be a menace back there.
And this is coming from someone who was not and still isn't convinced of him. Many folks tend to go overboard when they see someone young put in stellar performances, just like today when you see some automatically rule them out after a game, so be advised that many posts you read are hyperbole. Caceres has put in a fair share of good games and extremely poor ones, but so have other players in Juventus, even the likes of Moli who had a free ride for two full seasons as a starter.
Lets wait until the end of the season to judge his ability. Hopefully he will improve. WHo knows, maybe even his price could come down after this.