"The hierarchy at Chelsea and the supporters at Chelsea must just be hoping that it's going to take a year for these new players to bed in and get a look at the Premier League and then they'll kick on," Souness told talkSPORT.
"Enzo Fernandez, Moises Caicedo they're not really showing 100m-player qualities right now. They have to improve.
"(Nicolas) Jackson up front has to improve too. They will all be hoping this is a learning year for them but they have to up their game.
"I try to cut them some slack because they're young but those three have to start turning up, and others. If they don't Chelsea are going to have to go again when it comes to spending money.
"Because if that's their quality they're a mid-table team, and that won't be acceptable to the owners or the fans. That's a group of supporters who are used to winning silverware."