Supposedly, it was "Harden or Ibaka", not "Harden or Perkins". Amnestying Perkins wouldn't give them much capacity. Sure, you can fit 4 contracts in the salary cap, and the other 8 players on the roster?
That was them thinking about offering contracts. If they could amnesty Perkins, and I thought they could because I had seen it discussed at the time, it would give them all the capacity they need. $9M is not much capacity? That is a ton and can make all the difference. Is why we amnestied Scola.
I mentioned this earlier in this thread, but if they amnestied Perkins and gave Harden a MAX (Harden was not even asking for a max mind you, but let us pretend he did), they would essentially be paying next season what they are paying now, but for 10 players on the roster. Add a pick or use an exception and you're at 12. Would in reality have been even more favorable as Harden was willing to take a small paycut, but as mentioned, wanted a no trade clause.