Former Celtic midfielder Alan Thompson insists whoever replaces Neil Lennon in the Hoops hotseat has to quickly eradicate the negative feeling surrounding the club.
The Parkhead side are close to announcing Ange Postecoglou as Lennon's replacement, with the green side of Glasgow enduring a miserable campaign last time out which saw their fierce rivals Rangers canter to the Premiership title.
Ex-Celtic coach Thompson believes the club's new boss has a huge summer ahead of him, with recruitment and picking a new captain key decisions ahead of their crucial Champions League qualifiers starting after the Euros.
The 47-year-old also insists they must also rid the club of the negativity that festered towards the end of Lennon's reign, with the ex-Celtic manager accusing certain players of letting him down before he lost his job.
Thompson told Sky Sports: "If you look at managers over the previous years when they've been successful, you've got to engage with the fans.
"You have to play a style of football and second in Glasgow is nothing. You have to win games, ultimately.
"It's a huge summer for them. There's a lot of recruitment to be done, players that will be moved out to other clubs.
"He needs to appoint a new captain now that Scott Brown has left the club after so many successful seasons. That's a big decision for the new manager.
"It's a huge job and I'm sure the new man coming in wants to get going ASAP and get to work.
"I watched a lot of the Old Firm games (last season) and Rangers were dominant. It's down to the manager and the new group of players to change that.
"I know Neil Lennon feels like the players let him down last season, so it's up to the new manager to come in, recruit well and get the positive vibe back around Celtic Park."
