The 32-year-old will try to regain his world title belts for the second time when faced with Ukrainian in Saudi Arabia next month.
A potential unification fight with Tyson Fury could loom for Joshua if he can secure victory, but former champion Haye thinks a defeat could spell the end of his fighting career.
“If he doesn’t win, I’m not sure AJ wants to play in a sport where he knows he’s not the best,” said the 41-year-old.
“He was chased away by someone he knows can beat him; he’s just wrong. If he has a great game plan and does everything he has to do to beat Usyk, and Usyk still beats him, what else is there to do?
“He is not number one then. He’s such a winner… is he regrouping? I’m not sure. At the moment he believes he has all the possibilities to beat Usyk, and I think he has that physically too. All he has to do is get it right tactically and he should be able to defeat Usyk.
“Hopefully his team gives him the right instructions and he can go out and fulfill what most of us believe is his destiny.”