John Hartson believes former Celtic team mate Neil Lennon's time as Parkhead boss should be up.
The Hoops concluded a calamitous week with a goalless home draw against Livingston on Saturday which delivered another blow to already ailing hopes of a 10th successive Scottish Premiership title.
Lennon, assistant John Kennedy and 13 first-team players were still self-isolating as close contacts of Christopher Jullien who was confirmed to have contracted Covid-19 after returning from a controversial training camp in Dubai.
First team coach Gavin Strachan was in charge for the 1-1 draw against Hibernian last Monday night and again for the visit of in-form Livi who were a match for the weakened Hoops side.
The result left the champions 20 points behind Old Firm rivals Rangers at the top of the table with two games in hand, before the Light Blues' visit to Motherwell on Sunday lunchtime.
Former Wales striker Hartson has been a big supporter of Lennon, with whom he played with at Celtic Park between 2001 and 2006, but believes it is time for the Northern Irishman to go.
He told the ten10podcast.com: "I am a pundit but I care like the fans care, I am a Celtic supporter and ex-player and it is just very disappointing to see how this season has so fizzled out. I think a change is needed.
"I send Neil best wishes and good luck when he needs it but to lose the league in such a big, big season in the way they have, has been so disappointing.
"Not just me, look at Chris Sutton, Stan Petrov, Alan Thompson and Henrik Larsson (former team mates), we all love Neil and want him to succeed and we were all delighted when he brought home the quadruple treble but I do genuinely think, with the situation in the league, a change is needed from the bottom to the top, I really do.
"The whole thing needs to be changed and it needs to happen pretty soon.
"Maybe the players need a different voice. Neil might want a new challenge, a fresh start. Sometimes it doesn't work, Neil is intelligent enough, he has to see this.
"It has taken me this long to say I would like to see a change, new staff, a freshness, something different. Neil has done amazing. His trophy haul has been fantastic both as a player and a manager.
"I just think the club need to say that they are going to change the manager, whether he goes at the end of the season or now, it is tough call for me to say it but I think it needs to be done. The time has come."
Hartson believes the Celtic players should be glad no supporters are allowed into Parkhead this season due to the coronavirus restrictions.
He said: "I actually think it is a blessing that the fans are not allowed in because at this moment in time there would probably be about 15,000 fans watching Celtic.
"I think a lot of them would have stayed away having watching some of the drizzle Celtic have shown up this season.
"I think the players have got away with murder. I played at Celtic Park for five years and I had the Celtic manager and the crowd barking down my throat every time I gave the ball away.
"The players are giving the ball away willy-nilly now, the passing is not crisp, not accurate, there is a lot of sloppiness going on.
"The defenders are not winning tackles and interceptions, the crowd would go berserk, you would be booed off half the time.
"That has not happened so in a way you could say, yes, they have missed the crowd but they would get on to them and make it more difficult. How much stick would they be giving Shane Duffy now?"