1. We've seen some ridiculous salaries given out this offseason. Maybe that's the going rate for the 2nd or 3rd string centers.
2. We also don't have anyone playing center other than Amir. I'm presuming Olynyk will not be back until January. Also, presuming Horford doesn't want to play the 5. Mickey isn't on Brad's radar. Add to this, that there may be a dearth of quality big men out there.