A previous transfer from a 4-year school disqualifies an athlete for the one-time transfer exception. However, he wouldn't need the exception if he goes to a juco.
The rules for transfer from a juco are in the NCAA's two-year transfer guide. There are caveats, but in general a 4-2-4 transfer does not have to sit out a year as long as they spent a full year in juco and graduated.