I agree with Drucci and Brendan's sentiments of a Green/Pierce 2/3 combo. This is especially deadly and versatile offensively, and that would be with either Rondo or Dwest at the 1, it wouldn't matter even if Arroyo was the 1.
On defense, Green, with his foot-speed and mobility will better be able to cover the 2 than the 3, and those attributes, combined with his length should make him a real effective defender of SGs where he can bother shots on the perimeter, and if they get by him, block shots from behind.
If he keeps playing like he played last night, I think he should be first off the bench for both Ray and PP.