Bellator welterweight Rory MacDonald once lived in Georges St-Pierre’s shadow. A training partner of “Rush,” his early career was defined, in part, by his relationship to the former UFC welterweight champ.

Back then, St-Pierre was a mentor to MacDonald. But now, MacDonald is his own man, training in British Columbia, far away from St-Pierre’s Tristar home in Montreal. He’s a star in his own right with Bellator.

That means MacDonald is a spectator to St-Pierre’s (25-2 MMA, 19-2 UFC) return like everyone else. He’s not quite sure how the once-dominant force in MMA will look when he takes on middleweight champion Michael Bisping (30-7 MMA, 20-7 UFC) at UFC 217, which takes place Nov. 4 at Madison Square Garden in New York.

“It will be hard to say, because we haven’t seen him in a while,” MacDonald (19-4 MMA, 1-0 BMMA), who next faces Bellator welterweight champ Douglas Lima, told MMAjunkie. “That’s the exciting part.”

The 36-year-old St-Pierre was a master at transitioning from striking to wrestling, always keeping his opponents off balance. But his opponents were a lot lighter.

St-Pierre repeatedly resisted the idea of moving to middleweight when the division was owned by Anderson Silva. He argued he would need years to bulk up to combat a size disadvantage. After years of rumors of a potential super fight, St-Pierre stepped away from the sport as a welterweight.

“The 185 thing, I probably wouldn’t have advised it, but he is his own guy,” MacDonald continued. “He has his own goals. He’s obviously very talented.

“He is the most dominant champion in welterweight, and one of the most dominant champions ever. It’s hard for me to say what’s right and wrong to a guy like that.”

St-Pierre, after all, has already showed the world he can come back from a serious deficit. Many questioned his future when he suffered back-to-back ACL injuries, and still he returned in peak form to defend his belt.

A self-imposed four-year layoff is an entirely new hurdle, though.

If MacDonald hadn’t experienced St-Pierre’s meticulous preparation first hand, he might be more doubtful of the experiment. Like a lot of people, he has his questions about what will transpire. But he still believes in his old mentor’s abilities.

“It will be interesting to see what new skills he brings in there, or if he’s going to revert back to his natural strengths,” MacDonald said. “I’ll be watching. I hope for the best.”

Check out the above video to hear more from MacDonald.

And for more on UFC 217 and “Bellator: Lima vs. MacDonald,” check out the MMA Rumors section of the site.