Georges St-Pierre has been told it's time to step into the unknown and fight Anderson Silva, by his own training partner Frankie Edgar.

St-Pierre has been going back and forth, thinking over a step up to middleweight in order to take on Silva in a battle for the tag of best pound-for-pounder in MMA.

Doubts have been expressed by both St-Pierre and UFC president Dana White over a potentially unbridgeable size inferiority in comparison to Silva, while GSP has also stressed the dangers that moving weight can hold for a fighter's career.

However, lightweight champion Edgar has witnessed St-Pierre's quality at first hand and, if GSP beats Jake Shields on Saturday, he believes the time is right for the Canadian to enter the defining fight of his career.

"There's always going be someone new coming up to challenge you, but right now he has cleaned up the welterweight division almost twice," Edgar told Tatame. "So, it's going be tough for him to get some challenges, but I'm sure there'll be kids coming up.

"As a fan, I would love to see him fighting Anderson Silva. As a team-mate and friend, it's up to him.

"I think his best bet is getting him to the ground, and for Anderson is standing up. But I think Georges is more dynamic than most of the guys Anderson has fought, but as I said: Anderson has [been] running through everybody. So, as a fan, that's a fight I'd love to see."