UFC president Dana White says the Montreal mixed martial arts star has asked to fight Diaz next.
White told reporters Thursday that St-Pierre (23-2) made the request after returning from vacation following his welterweight title defence against Carlos Condit at UFC 154 in Montreal.
"We were talking about Anderson Silva," White said. "He (St-Pierre) said 'I want Nick Diaz. Me and Nick Diaz have unfinished business. We were supposed to fight. That's the fight that I want.'
"Georges St-Pierre has been a phenomenal champion, a phenomenal human being, just a great guy to deal with for us. And he doesn't ask for things. So if he wants to fight Nick Diaz and Nick Diaz wants to fight him, then that's probably the fight we'll make."
St-Pierre and Diaz were slated to fight last year but White yanked Diaz, who does not play well with others, for being a no-show at news conferences in Toronto and Las Vegas.
Diaz was replaced by Condit but St-Pierre injured his knee in training. Condit then beat Diaz in February for the interim title, earning the right to meet the Canadian champion in Montreal last month.
Diaz (27-8-1) was hit with a one-year suspension after the Condit fight for testing positive for marijuana.
White said he has yet to talk to the 29-year-old Diaz about a GSP fight. But that may happen this week since Nick is in Seattle to watch his younger brother Nate take on Benson Henderson for the lightweight title Saturday.
St-Pierre's coach Firas Zahabi raised Nick Diaz's name in talking to reporters Wednesday, saying more fans in Canada ask him about a GSP-Diaz fight then GSP-Silva. He said it was the other way around in the U.S.
The St-Pierre camp has said their fighter is up for a lucrative Silva fight. But they have said they will only do it in the right circumstances — and at the right weight.
St-Pierre is currently in Europe. Reached by The Canadian Press by text, he declined comment until he returned home.
The 31-year-old Canadian champion has to cut to weigh in at 170 pounds as a welterweight. Silva, the middleweight title-holder, has to make 185 as a middleweight and has fought at light-heavyweight (205).
Silva is a bigger man. And the St-Pierre camp wants to make the playing field as even as possible.
A fight with Diaz gives them more time to negotiate the super-fight. And GSP-Diaz is seen as a crowd-pleaser.
Asked if such a fight could take place at Toronto's Rogers Centre, White paused.
"It's a good question. Yeah, I think it's a big fight. It's a fight that everybody wants to see. Its an interesting fight."
St-Pierre helped fill the domed stadium when he beat Jake Shields in the UFC's first visit to Ontario at UFC 129 in April 2011.
The UFC boss said he had no timetable for the bout.
"I was trying to track Nick down this week, which is always fun," White said. "So I called Nate, and Nate told me five days ago 'Listen if you talk to him, tell him I'm looking for him too.'"
A GSP-Diaz fight is bad news for contender Johny (Bigg Rigg) Hendricks, who thought he had the next title shot after dispatching Martin (The Hitman) Kampmann, Josh Koscheck and Jon Fitch in compiling a five-fight win streak.
"I don't really know what to say but please @danawhite give me a shot @GeorgesStPierre if u want a fight I will give him anything he can take," tweeted Hendricks (14-1).
Said White: "Listen, Johny Hendricks has had some great fights. When you talk about winning in spectacular fashion, this guy hits people so hard they skid across the Octagon. He's is no position to demand anything. Georges St-Pierre's the champ, has been ever and if that's the fight he wants, then that's probably the fight we're going to give if Diaz accepts it."
White still believes Silva will end up facing both St-Pierre and light-heavyweight champion Jon (Bones) Jones.
"The beauty is the greatest fighter in the world weighs 185 pounds and he falls inbetween No. 2 and No. 3 best pound-for-pound in the world. He can fight either one of them. I think he'll fight them both before his career is over."
White says big-money paydays help sell super-fights but athletes like Silva also want to challenge themselves.
"And when has Anderson Silva never stepped up to the plate and done what we've asked him or needed him to do. Even fighting at 205 (pound) on a month's notice."
White and UFC co-owner Lorenzo Fertitta met with Silva on Wednesday.
"We've got some fun things for Anderson too," White said.
"He'll fight anybody," he added. "And he knows he'll win if he does. That's how he talks behind closed doors."
The UFC gave the 37-year-old Brazilian a Bentley Continental GT, worth a resorted US$174,000, to thank him for meeting Stephan Bonnar in Brazil on short notice.
"Anderson stepped up and did up a big favour down in Brazil," said White. "So we did him a favour."