The three-year deal was in place from Fox's loan move to Forest in January, the 29-year-old left-back having made 15 appearances to date for the club.
Speculation has already begun of course about which players wil be leaving and arriving at the City Ground over the course of the summer but concrete news may be hard to come by as the football world begins to take its holidays and then settles back to watch the World Cup in Brazil.
With Stuart Pearce not officially taking over until 1 July and having some other commitments before then there may be a lull in the transfer talk that keeps us all going until then.