I usually don't complain about the refs, but some statistics do raise some concerns about how the centers are being reffed.
Yao averaged 3.53 fouls per 36 minutes in the regular season. In the playoffs, it's been 2,88 per 36 minutes. So his foul rate is down by 18%.
For Pryz, its 3.91 in the regular season and 5.07 in the playoffs, for an increase of 30%.
Oden has had foul troubles all year. He's at 7.09 for the regular season and 10.29 for the playoffs. This is an increase in his foul rate of 45%.
If you average Pryz and Oden, they are fouling at a 38% greater rate than during the regular season.
So while Yao is fouling somewhat less, the Blazers are fouling way more. Accounting for Yao's drop and the Blazers' increase, relative to Yao, Pryz is up 58% and Oden is up 77%. If you average Pryz and Oden, since both play about half time, Pryz/Oden's foul rate is up 68% compared to Yao.
1) Yao is so much harder to defend that the Blazers foul him 38% more oftern than normal centers while playing with normal aggression,
2) the Blazers have upped their aggressiveness by 38%, or
3) the refs are calling fouls differently than in the regular season (despite the adage that playoff basketball is tougher).
My rough guess is that Yao does pose a more difficult challenge, but it's not 38% more fouls worth. More like 10% more fouls worth. And the Blazers probably are player tougher (but only playoff tougher). Again, I think this is in the 10% range. So the biggest portion (the other 18%), and almost as great as the other two effects combined, is the refs lowering their tolerance for fouls.