Earlier this week, UFC president Dana White confirmed his interest in booking that matchup for UFC 227 on Aug. 4 in Los Angeles. Sources have told ESPN that Diaz is open to fighting on that date, against an appropriate opponent.
In a Facebook post on Friday, Diaz, 33, hinted the bout is far from done. He also brought up some history between St-Pierre and his older brother, Nick Diaz, who challenged and lost to St-Pierre for the UFC's welterweight title in March 2013 in St-Pierre's hometown of Montreal.
Nate Diaz demanded St-Pierre set the record straight on a few things.
"[St-Pierre] cheated when he fought my brother," Diaz alleged in his Facebook post. "He was on steroids. He was overweight and they let him be, because we were in Montreal, and his boy gave Nick a bad IV. Now, they are selling [you] wolf tickets on me.
"[St-Pierre], clear that s--- up or fight yourself, cheater."
St-Pierre, 36, has never tested positive for a banned substance under the UFC's drug-testing program. He has been one of the sport's most vocal advocates for increased drug testing.
St-Pierre did not immediately respond to a request for comment by ESPN.
During the week of their March 2013 fight, Nick accused St-Pierre of using performance-enhancing drugs and claimed the overseeing athletic commission was not properly testing them.
After St-Pierre won the bout by decision, Nick's team questioned how much St-Pierre weighed during the official weigh-in. In particular, they claimed an uncommon decimal allowance let St-Pierre weigh in heavier than the traditional 170-pound championship weight.
St-Pierre denied any wrongdoing in the matter, and the result of the championship bout remains a loss on Diaz's record.
The proposed bout between Nate and St-Pierre would be a major addition to UFC 227. St-Pierre has not publicly addressed the potential fight.