Chris Sutton has accused Celtic chiefs of "sitting on their hands" since Brendan Rodgers' return.
The former Hoops forward is unhappy with the transfer business, or lack of it, conducted this summer.
The 50-year-old insists it was far from a surprise to see Kilmarnock humble the Scottish champions 1-0 on Sunday.
And he's urged the Parkhead board to back Rodgers and tone down their apparent arrogance which has seen them drop out of the League Cup already this season.
He told the Daily Mail's 'All Kicking Off' podcast: “It was coming. It wasn’t a great surprise that Celtic lost that game from the evidence I have seen.
“I don’t know whether Celtic have been complacent or arrogant in terms of, they’ve already got Champions League qualification to the groups.
“I think they’ve sat on their hands too much during this transfer window.
“They let Jota go for £25million, Aaron Mooy has gone, they have injuries to key defenders and they let Carl Starfelt go.
“I thought that was a baffling decision as they should have kept him until the end of the window.
“Carter-Vickers and Starfelt were the rocks for Celtic under Ange Postecoglou. Celtic never lost a domestic game with that partnership. I think Celtic are weaker going into this season and it’s a worry.
“Now the pressure is on because Brendan, the first time around, got seven trophies out of seven domestically and is already out of the league cup.
"So that’s a worry and at this moment in time, looking at the Champions League where they are always up against it, the squad is looking really weak and short.
“What it might do though, is give them a kick up the backside to bring in, not just development players, but those who are ready to go into the first team and take Celtic up another level.
“Most of the Celtic support thought Brendan was the best man to come back for his coaching credentials and the best man for the job. But what we do know north of the border is that the climate can change very quickly.
“Seeing stuff online about how Celtic played, a lot of supporters are unhappy. They didn’t create opportunities and that could become a problem.
“They now play Rangers in a couple of weeks and that’s an enormous game, as Michael Beale hasn’t got off to a flier either."
