Marcelo Bielsa led Leeds to the Championship title last season and promotion back to the Premier League after a 16-year absence.
The Whites impressed many with their signings in the transfer window, and their early performances in the top flight which have brought seven points from four games, have won praise.
Wolves play Leeds on Monday evening and Bull, who sees the Whites as different to the way they used to be, is wary of a tough test being posed for Nuno’s men.
The legendary former striker insists that Leeds look as if they could do what Sheffield United did last term; the then newly promoted Blades finished ninth.
“Leeds, back in the old days, used to be rock-hard – not afraid to go through players and make their presence felt”, Bull wrote in his Express & Star column.
“Now, they are more of a footballing side.
“I have watched them a couple of times this season and fair play to Marcelo Bielsa, he has done really well with them.
“They have every chance of being the team that Sheffield United were last season, a bit of a surprise package, as they do not seem to fear anybody and have a set playing style.”
Wolves have collected six points from their opening four Premier League games and edged out Fulham 1-0 before the international break.