A whole bunch of guys could have put him down. Lewis, Bowe, Wlad, Foreman, Tyson - he didn't exactly prove his chin against a murderer's row.
I think this latest version of Haye carrying an extra 20 lb and with the extra power would most definitely be able to put him down.
Alrite I'll answer it honestly. 3 guys come to mind.. Wilder: hes tall, rangy, has good speed for a big guy and a hell of a right hand that I think can crack that yeti head of Valuev if landed flush. Joshua: Anthony has 17 knockouts in 17 fights, though his power hasn't really been proven against the elite chins of the division. That said he's still got a great chance at chin checking Valuev with a left hook he doesn't see coming, or overhand right on the temple. Ortiz: now this guy is just a monster in his own right. A southpaw with extreme punching power as was shown by stopping Jennings when Wlad couldn't do so. Secondly he's willing to take risks to land his punch, and I think he could knock Valuev on his ass with any punch in his arsenal minus the Jab imo. Anybody else? NAH!
Tyson, Foreman, Frazier, Bowe, Lewis, Bert Cooper, Ruddock, Bruno, Bonecrusher.... I think a lot of people could knock him down and out, maybe even Prime Holyfield could do it.