He is seeking compensation from Seyi Olofinjana and the midfielder's former club Cardiff City over a knee injury suffered in a match in November 2010.
Blackstock, 27, who scored the winner before being stretchered off, claims the midfielder was "negligent".
The amount has not been disclosed but exceeds £50,000, according to the writ.
Blackstock said Olofinjana, who now plays for Sheffield Wednesday, challenged him "in a way that caused a reasonably foreseeable risk of injury" in the 88th minute of the game, which Forest won 2-0, at the City of Cardiff Stadium.
Out for seasonHe has lodged a writ seeking damages for not being able to earn bonuses while he was injured and wants the right to further compensation should the injury end his career prematurely.
Blackstock's barrister, Jonathan Crystal, said in the writ that Olofinjana, 33, "played Mr Blackstock rather than the ball" and "raised his foot" in the challenge, "forcefully striking" his opponent's shin and calf and failed "to control his momentum".
"The medical reports detail a significant chance that at some point in the future Mr Blackstock's knee will deteriorate further or he will suffer further injury as a result of the existing condition of his knee which will impact upon his ability to play professional football."
Former Southampton and QPR player Blackstock returned from injury in December 2011 and went on to make 24 appearances for Forest in the 2011/12 season.
He played in 39 matches in 2012/13 but only played three times for Forest this season before joining Leeds on loan in October.
The former England youth international made four starts for Brian McDermott's side but returned to Forest in December after being ruled out for the rest of the season with a knee injury.