Stack became a Macedonian citizen after playing there for a few years. A lot of players do that when they play in some of the smaller European countries. It allows them to not count as one of the 2 Americans on a roster, which most European leagues limit teams to. Also, they can play for the national teams and they can get paid more and pay less taxes. I believe John Chappell did the same thing in Macedonia.
There are a lot of former Gamecocks who had solid careers and made good money playing overseas including but not limited too Jojo English, Larry Davis, the late Rolando Howell, John Chappell, Chris Warren, Carlos Powell, Renaldo Balkman, Tre Kelley, Chuck Eidson, Marius Petravicius, and Antonio Grant, Greg Taylor, and Dominique Archie