The Dutch striker signed for the Reds 20 years ago on the 9th March.
The Forest captain is close friends with his former team-mate.
The former Football League manager has predicted an away victory for Nottingham Forest as they travel to Rotherham
The striker has headed to Rotherham United.
The striker was released by Nottingham Forest this week.
The Antigua and Barbuda international left Nottingham Forest yesterday.
The striker is looking for a new club after struggling to get into Philippe Montanier's Nottingham Forest side this season.
Blackstock becomes the latest striker to exit the City Ground this week.
The striker has left the City Ground after seven years.
Forest lost 2-1 to the Seagulls, whose winner came in second-half stoppage time.