"In the 205 times he was posted up last season, Bargnani held his opponent to just 182 points (0.888 PPP) on just 46.8% shooting"
Ok sounds good, but how does that compare to the league? To other starting C's (or bigs)? This accounts only for when he is specifically posted up, and it also doesn't account for who is doing the posting up. (remember he always got the easier cover).
"When faced with isolation situations, Bargnani is in the top 17% of the NBA in terms of Points Per Possession (PPP) allowed, giving up just 0.684 points per possession on 29.7% shooting"
ok now we a number that offers a comparison, but how many times did that happen? How often did the team not send help? Again, who is this isolation against.... Ryan Hollins/Brandon Bass/Chuck Hayes/Biendrins?
"but he is able to go straight up and use his length to contest shots without fouling (fouled opponents on the block just 7.6% of the time) by going straight up."
I'd argue his lack of fouling is an indictment of how bad his defense is. Good/smart defensive players use their fouls. Good hard foul and 2 fts > dunk or lay up in my books.
Then the authors conclusion is Bargnani is a terrible help defender, Bargnani is a terrible rebounder (which is a defensive attribute), but he is not a terrible one-on-one defender (and it was only in post situations that the author tried to "prove" it). Therefore Bargnani is not a terrible defender? That Bargnani can be a good or average defender going forward if moved to PF (where he will play less post defense no less).