It's a fight Diaz wants badly, and last Thursday, he was in Las Vegas to meet with UFC president Dana White and ask for it. The results of that meeting are so far unknown, but we can report there is no deal done just yet. But we also know that White is often quite receptive to fighters who passionately lobby for a specific fight.
Though the bout is not official, many believe it's a more likely possibility than St-Pierre vs. Silva, and in the earliest odds released for the bout, St-Pierre has been installed as a fairly large favorite.
MMA oddsmaker Nick Kalikas has installed St-Pierre is a -425 favorite over Diaz, making him an over 4-to-1 choice to win. Diaz is at +325.
St-Pierre (22-2) is the winner of nine straight bouts and has defended his belt six times in a row since re-capturing it with a win over Matt Serra in April 2008. Just three weeks ago, he held off Diaz's Cesar Gracie teammate Jake Shields via unanimous decision.
Diaz, though, has an even longer win streak than GSP, boasting 10 straight victories, including his most recent, an April 9 knockout of Paul Daley that moved his record to 25-7 with 1 no contest. Given Diaz's boxing ability and attacking jiu-jitsu style, many feel his skill set can offer St-Pierre more matchup problems than any top-ranked welterweight.
The prospect of a Silva vs. St-Pierre superfight still remains a possibility, but St-Pierre would find himself in the role of underdog there. As it currently stands, Silva is a -175 favorite. The middleweight champ has other things to think about first, however. He is currently booked for a UFC 134 title defense against Yushin Okami.