He can stop Rahman, but he will have to be very smart a box flawlessly especially in the first few rounds. If he doesnt keep his defence tight Rahman can end the fight with one punch. Rahman is pretty bad but he is a vereran and he knows how to sneak punches in, plus he is a good puncher. I think if Haye utilizes his fotwork and straight punches he cand tire out the plodding Rahman and stop him in the middle rounds or take him to a decision.