Sheffield United's Ben Osborn will not rule out a dark horse emerging to challenge the Sky Bet Championship promotion favourites.
The Blades, Fulham and West Brom are expected to be frontrunners as they bid to bounce straight back to the Premier League after relegation in May.
The 2021-22 season kicks off on Friday with Bournemouth's televised home game against the Baggies and Osborn says it will be as unpredictable as ever in the second tier.
Midfielder Osborn told the PA news agency: "There will probably always be a team that takes you by surprise.
"The teams that the players have spoken about that are always going to be difficult to play against, your Cardiffs, Middlesbrough under (Neil) Warnock.
"Chris Hughton's Forest will always be a tough team to play against, the way they set up, and then you're going to get a team that might over-achieve."
Barnsley's unlikely promotion push last season ended in the play-offs, but they could struggle to challenge again after the departure of boss Valerien Ismael, who has taken assistant Adam Murray and skipper Alex Mowatt with him to West Brom.
"The surprise team this time could be a Luton, who have been together for a while now and got some good results last season and have added a couple of good signings.
"Millwall are always going to be tough to play against and they've made a couple of good signings.
"I played under Mark Warburton at Nottingham Forest and I was very impressed and really enjoyed my time under him.
"He wants to play almost total football and every time I see QPR I can see the kind of stuff that he's doing.
"They did tighten up towards the end of the season and again, if he can get them ticking and get a solid XI on the pitch who can play his kind of football, then they could be up there as well.
"It's such an unpredictable league, but you would expect the ones who came down and possibly Bournemouth to be leading the fight up there."
Osborn is quietly confident of the Blades' chances under new manager Slavisa Jokanovic, who has twice won Premier League promotion with former clubs Watford and Fulham.
"Certainly we want to be up there," Osborn said. "It's tough, the Championship is always tough. Obviously the other two teams that came down will want a strong challenge as well.
"But we definitely want to be up there and the way we're going about things in training, the way we're looking to play and take the game to teams shows we'll be going out more often than not to win games of football.
"The lads have really taken to the gaffer and his staff, trying to implement something a little bit different. He's certainly impressed us.
"Everyone knows his history and the lads were excited even before he started working with us."
