I think they brought Wilder in for the sole plan of punching Haye really hard in the head. Just to try and toughen him up a bit for Fury's heavy hands. Who knows what goes on in those sparring sessions, could have been a round of Wilder throwing bombs and Haye just trying to defend. Or it could have been a straight forward spar and he really did knock Haye out. We'll probably never know.

If Haye did get knocked out, the Fury match will be very boring as Haye will bring out the Valuev playbook and just avoid him all night.