The Hoops defender admitted he was "guilty of an error of judgement" after playing in the 1-1 draw at Rugby Park and the ramifications of breaching Covid-19 protocols have been severe.
Neil Lennon's side's next two games against St Mirren on Wednesday night and Aberdeen on Saturday have called off by the Scottish government, as have the Dons' matches against Hamilton and the Hoops.
Aberdeen's visit to St Johnstone was postponed on Saturday after two of their players tested positive for Covid-19 and a further six were instructed to self-isolate following a night out.
Ahead of the away trip to Ross County on Wednesday night, Killie boss Dyer said: "We do the right thing and I know Celtic do the right thing
"I know they didn't know because I know Neil and I know what he is like as a human being, and I know some of the staff there and they are good people.
"I know they wouldn't have put a lad out in front if they knew beforehand. It is a mistake and we just need to move on now.
"They have been in touch and they apologised. They (Celtic) have been tested twice again and it came back negative so hopefully there is no danger there.
"Our boys were tested yesterday and as far as I know everything is in order to we look forward to playing against Ross County."
Dyer noted that the Staggies have started the season with two wins out of two.
The Rugby Park manager, hoping to get anew goalkeeper into the club in the next few days, said: "The lads worked hard against Celtic and did the right things.
"Everyone was very good, it was a good point and hopefully we can go to Ross County and try to do the same.
"It will be tough game, they are very good side and well organised.
"They are a confident bunch, they've won two games but we have to go there and try to get the points."