Rival Championship boss Mick McCarthy has revealed Rotherham United are one of the teams he fears next season.
McCarthy is determined to see his Ipswich Town side pushing for a play-off spot after finishing ninth last year.
But he acknowledged the Tractor Boys face a tough test and says the Millers are a team to look out for.
“Rotherham have come up from League One. I thought they were a good side last season and they’ve spent a few quid,” said the 55-year-old.
“I see Wolves as a threat as they totalled over 100 points in League One last season and Kenny Jackett has put a good, young team together,” he said.
“He’s re-signed Stears (Richard Stearman) as a bit of experience in the team. They are a big club with big support and they will be a threat.
“The lads coming down, Norwich, Fulham and Cardiff, will all have good squads, depending on who they lose, and will be in a position to buy, so it is going to be hard.”
Manager Steve Evans has brought in 10 players since the Millers achieved successive promotions by winning the League One Play-off Final in May, having already signed Conor Newton on the eve of the Wembley showdown with Leyton Orient.
Despite McCarthy’s claim, only one new arrival has cost Rotherham a fee.
They broke their transfer record to prise ex-Chesterfield striker Jordan Bowery from Premier League Aston Villa, but all the other signings have been free agents.
Icelandic left-winger Johann Berg Gudmundsson, who was a target for Rotherham, has joined Charlton.
Evans’ men play the first match of their Scottish tour when they face Greenock Morton, kick-off 3pm. The players travelled north of the border on Thursday.
Rotherham’s opponents on August 9 opening day, Derby County, have signed defender Cyrus Christie from Coventry City for an undisclosed fee.