Terrible game plan having Sully post up against the Magic bigs. He should had been facing up from 15 feet out and taking advantage of how slow those guys are.
The point of Sully posting them up is that Vucevic is a poor defender and Sully can take him 1v1 or draw a foul as a last resort, but the main reason they post Sully up is because the Magic love to help in the post given Vucevic's poor post D (as with every other position within 15 feet), so he drags in the help defender and kicks out, or dishes to a cutter like AB or Turner.
But yeah, they aren't trying to score 1v1 with Sully, just draw defenders away from the perimeter.
eg:
Post up Sully. He backs down. Help defender comes. He kicks out to Crowder. If Crowder doesn't have an open shot, he swings to Bradley in right corner (favorite spot from 3), if Bradley isn't open he swings to Amir, who swings to IT in the left corner (favorite spot from 3).
If IT can't get shot off, he penetrates and looks for Crowder or Bradley who are waiting at the top for a dish.
Sully's post ups are just another form of penetration. You'll see this vs longer/length teams with good help defense where dribble drive & dishes by Isaiah and Turner are harder to get open looks with.
The problem with this play is that our only good 3 point shooters are IT and Bradley lol.