If Hakuho makes it past day 5, it's his tournament. Kakuryu recently won the cup and finished runner up before that, so I suspect Kak will show up for a fight or two, grimace at the end of a fight, then go kyujo and rest his knee like he should. Those are the only two legit contenders. The rest of the upper ranks are a gong show, and Takayasu and Tochinoshin are probably hoping to hold/get ozeki and will likely not try too hard if it risks hurting themselves further. Goeidou is Goeidou, and Mitakeumi strikes me as Goeidou 2.0. I don't believe Takaeisho that he's healed.
So if it's not Hakuho, my money is on Asanoyama.