Chief executive Peter Lawwell has admitted Celtic's controversial decision to go to Dubai for a mid-season break was a "mistake" and has apologised to Hoops fans.
The Parkhead club confirmed Christopher Jullien tested positive for Covid-19 but all others and staff members were negative after being checked following their return to Scotland from a training camp last Friday.
However, 13 players, manager Neil Lennon and assistant John Kennedy were deemed to be close contacts and had to join the French defender in self-isolation and amid widespread criticism, it was a makeshift Celtic side which drew 1-1 with Hibernian on Monday night.
Speaking in an in-house interview on the club's official website, Lawwell said: "It has been an extremely difficult few days and on reflection, looking back and with hindsight and looking at the outcome of the trip, clearly it was a mistake and for that I profoundly apologise to our supporters.
"We left here and the rationale for the camp was very much with the best intentions. Things haven't gone the way we wanted to and the outcome is clearly very regrettable."
The draw against Hibs left Celtic 21 points behind Rangers at the top of the Scottish Premiership with three games in hand and with their bid for 10 in a row in some jeopardy.
Lawwell said:"If you look back over the last four years, going to the camp in Dubai has been extremely successful.
"And the decisions we made in entirely for the best interests of the team and the best interests of the club.
"What we planned to do was take them to these facilities again, which are world-class, after a very hectic programme in November and December, which has in the past proven to be a great benefit in terms of performance after January, to get to that performance level again."