There are two reasons to start Ish at PG over Green at SG. As mentioned, Ish is a far better ball handler than Green and more natural at it than Bledsoe.
And Green's temperament is too fragile to jockey him back and forth between bench and starter. Each one seems to require time for an adjustment on his part.
That being said, I expect that Jeff would start Green over Ish.
Even on a bad ankle, if Goran could pull a Willis Reed, play a few minutes and make a couple of jumpers, it would give Jeff a lot more flexibility in working in Ish.