The 30-year-old Hungarian announced he was taking a break from the game back in June but will now be looking to return to action after getting the go-ahead from doctors in Budapest following his recovery.
Fulop, who is a free agent, has already resumed training with a view to being back to match fitness by the end of the year.
He will continue to have regular medical check-ups over the next five years.
He made 50 appearances for the Black Cats in total.