I wonder if it will be for practice only, since the qualifying games are played Sept. 3-20, 2008, and the Championships are Sept. 7-20, 2009. That would be a lot of classes to miss. There are 18 guys on the roster according to the link. The Link
It's my understanding he'll be in Austin working with his teammates during the first summer session, then heading to Turkey for the second session, but he'll be back before classes start.
That may not be correct, but that's my understanding at this point.
I believe his participation on the national team this summer is more for preparation purposes than to actually contribute significant minutes. I don't know about the rest of their personnel , but Engin Atsur is a quite capable point guard in his own right, so the need for Balbay to play a critical role for the team is probably minimal.