Semi has the physical upside/athleticism to be a great player in this league. Yabu will battle weight (see big baby, Sully) his whole career and likely underachieve because of it. No one knows for sure, but I'd put my money on semi if I had to choose one.
He has yet to battle weight in any way shape or form up to this point. Dude is ripped. Know your personell.
He's going to battle weight issues because he's going to be a step slow due to his size. That said, Sully is a poor comparison. Yab is 260-270 pounds of muscle. Sully is all fat.
LBJ and Yabu are both 6'8". LeBron is listed at 250 and Yabu at 270. I'm having a hard time believing all of that 20 pound differential is muscle...
Anyway, wherever Yabu is carrying the weight, he's carrying it. And, physics. He moves very well for a man so heavy, but that's not the same as moving well. Too much inertia. I'm hopeful he'll be able to play underneath a lot, because I can't see him being effective switching onto wings on the perimeter. I'm also concerned that he's out now with a foot injury. Carrying all that weight in the open floor can't be easy for a body to sustain.
One more comp. Draymond Green is an inch shorter than Yabu at 6'7", and listed *forty pounds* lighter, at 230. Draymond is not a skinny guy.