According to an NCAA bylaw, a player who is dismissed from a team for any reason counts against the team's number of scholarship athletes for the remainder of the academic year.
Here's the bylaw:
220.127.116.11 Cancellation of Aid.
Once an individual becomes a counter in a head-count sport (see Bylaws 15.5.2, 15.5.4, 15.5.5, 15.5.7), the individual normally continues as a counter for the remainder of the academic year. However, if he or she voluntarily withdraws from the team prior to the first day of classes or before the first contest of the season (whichever is earlier) and releases the institution from its obligation to provide financial aid, the individual no longer would be considered a counter (see Bylaws 18.104.22.168 and 22.214.171.124.1).
So, if Miles had left on his own accord before the school year started, UConn could have used his scholarship on someone else. But since he was expelled from school, his scholarship can't be used, unless UConn is granted a waiver. But it's highly doubtful that would happen.
So, the Huskies essentially will have 12 available skollies for 13 players, assuming both Robinson and Ater Majok, a 6-10 incoming recruit from Australia, make it to campus by mid-December. It appears likely that both will be here by that time.
Robinson, currently working full-time as a sheet metal worker but working out with the team as often as possible, would likely have to pay his own way for the second semester. But he should be able to get enough financial aid where it wouldn't be a huge burden.
(P.S. -- that bylaw would also seem to indicate that Miles will count against UConn's graduation rate, as well.)