You don't think even without the best training equipment or whatever someone said in this thread that a guy like Kevin Durant wouldn't score on headers from corner kicks like every game?
The Slim Reaper would get bodied out of the way in a corner kick every single time, then his team would get scored on when KD tries to lumber back to centerback, about the only position where his frame wouldn't be a massive liability.
Imagine someone insanely quick with ridiculous footwork like Allen Iverson choosing soccer instead of basketball? Someone as long and explosive as Lebron playing goal keeper.
Allen "Hero Ball" Iverson would be a turnover machine though. Unless we're arguing that he would have Xavi-like vision, but there's not much that suggests that would be the case.