Striker makes claim for damages after tackle.
Blackstock is seeking compensation over a tackle in a Championship clash between the two clubs at Cardiff City Stadium in November 2010 which put him out of the game for 15 months with an "horrific" knee injury.
Blackstock claims that 6ft 4in Olofinjana, who these days plays for Sheffield Wednesday, was "negligent" in "failing to play the ball" and "challenging (him) in a way that caused a reasonably foreseeable risk of injury" in the 88th minute of the game.
Blackstock had scored in the League encounter before being stretchered off following the tackle, which prompted his then manager - Billy Davies - to call for an official complaint.
Blackstock, of Popplewick, Nottingham, has lodged a writ at London's High Court, seeking damages for being deprived of the chance of earning bonuses for 15 months, as well as the right to further compensation should the injury end his career early.
In the writ, Blackstock's barrister Jonathan Crystal claims that Olofinjana "played Mr Blackstock rather than the ball" and "raised his foot" in the challenge, "forcefully striking" his opponent's shin and calf and "failing to control his momentum".
Blackstock endured "pain and loss of amenity" and Mr Crystal claims that the manner of the tackle carried with it "a reasonably foreseeable risk of substantial injury to him".
The barrister continues: "The medical reports detail a significant chance that at some point in the future Mr Blackstock's knee will deteriorate further...
in the event that this occurs, Mr Blackstock will be entitled to apply for further damages."
The amount that Blackstock is claiming has not been specified in the writ, other than that it exceeds PS50,000. The defences to the action of Seyi Olofinjana and Cardiff City FC were not available from the court, and the contents of the writ have yet to be tested in evidence before a judge.