I see Yi playing back up pf as well, Blatche I don't think can handle playing full time center and is better than Yi at the power forward, at least for now.
Good news though, Yi has been dominant in Fiba this off season thus far:
26 points (9/15 shooting) 14 rebounds vs Greece
26 points (9/17 shooting) 9 rebounds vs Cote d'Ivoire
Competition isn't NBA level of course, but still good to hear nonetheless.
Some highlights against Greece:
Video quality sucks, Yi is number 11.