Former Celtic star Charlie Nicholas believes the Premiership champions will have a real 'problem' with playing competitive matches without fans.
The Sky Sports pundit reckons Neil Lennon 's side will find it more difficult than most in adapting to life without their adoring public roaring them on to start the season.
And concerned Nicholas insists his former side haven't been active enough in the transfer market ahead of their Premiership opener against Hamilton on Sunday.
It comes with Celtic closing in a double deal for £5.5m keeper Vasilios Barkas and a season-long agreement for West Ham forward Albian Ajeti.
But despite the signing boost, Nicholas doesn't believe his former side will be celebrating another domestic clean sweep this time around.
Speaking in his Express column, Nicholas said: "I am a Celtic fan. I want another Treble, I am not camouflaging that but I do think Celtic will have a problem with no or limited crowds.
"I think they will find it the hardest to adjust to that lack of energy they get from 60,000 fans every second week.
"That is a massive thing to lose and I can see it causing Celtic a stumble, especially in one of the cups.
"If Nicola Sturgeon decides to continue to take control then the best we can hope for is very small crowds, but if it is long-term then Celtic would be impacted more than any other team.
"The other major worry I have about the club is that they have lost a few players and don't have the same numbers in the squad.
"The new season is action-packed and it will be relentless with Europe and internationals.
"It might be that Celtic need to prioritise and if they were to look at the trophies then the Betfred Cup is probably the least important now.
"It is a competition that has lost its way. I have won it a couple of times but it is one that Neil Lennon could look to play some of the youngsters and fringe players.
"Celtic will still want to win the Betfred Cup, of course they will, because they are used to winning everything."
