Morgan feels the three sides relegated from the Premier League - West Brom, Middlesbrough and Newcastle - will be pushing for an immediate return and picks out the Blades and Nigel Pearson's newly-promoted Leicester as other challengers.
Morgan said: "It's difficult to compare our squad with last season's, although we've always had a strong nucleus of players to choose from. Preparation starting in pre-season is vital. We began well at Middlesbrough and it's important to have built on that.
"Everybody knows the three teams coming down from the Premier League are going to be strong. All three have good squads and should be there or thereabouts.
"There are other teams in this division that are always challenging, while Leicester, just promoted, have started really well and are one of the best sides we have played in my opinion."
The Blades drew 1-1 at Bramall Lane with Leicester in August, with Keith Treacy cancelling out Matty Fryatt's second-half opener for the Foxes.