For some reason I think Chael.
Back to basics wrestling against a slower Fedor. His wrestling still works and I think he'll hump Fedor on the ground. The question is whether he can do it for 3 rounds...?
If he can take Rampage and Wand down and control them, I don't see why he cant take an aging Fedor down, he might just sub Fedor if Fedor isn't careful
His submission grappling has improved considerably, he almost caught Tito and he competes quite regularly at world class events - Metamoris, ADCC, etc.