If he fought at super featherweight definitely, lightweight is a bit tougher and i'd prefer to see him have 1 or 2 10 rounders first
Audley Harrison was top 15 when he fought haye?I'm not sure its even possible. Even a voluntary defence has to be a top 15 and if the opponent isn't they're generally bumped up the rankings after the fight is made. I'd suggest it'd be impossible for a guy with no fights to gain a ranking but this is the WBC/WBA/WBO/IBF we're talking about...