"If we encountered a situation with a proper gameplay context, we would consider it. Let's say if we were building a level and functionally it called for someone to throw barrels at you, then Donkey Kong would be appropriate. But now that I think about it, maybe we have a situation where, at the end of Super Mario 3D Land, Bowser throws fireballs at you from the end of the stage. And we didn't use Donkey Kong there… so…" - director Koichi Hayashida

Looks like Donkey Kong is going to stay Mario's rival on the sports scene, but a main-game entry with DK as the big baddie doesn't look too plausible.