The Scottish Football Association is set to announce the result of its investigation into the Dundee United v Celtic match later on Wednesday.
The fall-out from the 17 October game, in which Celtic had a penalty award overturned, led to assistant referee Steven Craven resigning on Monday.
Craven has decided to stop officiating professional matches.
Celtic manager Neil Lennon was furious that referee Dougie McDonald changed his decision after consulting Craven.
United keeper Dusan Pernis had rushed from his goal and prodded the ball away from Celtic's Gary Hooper but his momentum took him into the striker and sent him tumbling.
The match officials were subsequently praised by the SFA's head of referee development, Hugh Dallas, for getting the decision correct.
Hooper scored a last-minute goal to win the match for Celtic.
Speaking on BBC Radio Scotland's Sportsound on Monday, former grade one official Kenny Clark was disappointed to hear of Craven's resignation.
"I'm certainly not going to criticise him for taking that decision because I don't know how much abuse he has had to put up with. I don't know what his family have been subjected to," said Clark.
"The more pressure that is heaped upon referees, the more abuse that is directed at match officials, the more difficult the job becomes.
"The fewer people attracted into refereeing or acting as assistants, then obviously quality will diminish.
"We need to have as many people as possible coming into it and then you can sort out the good one from the poorer ones.
There have been occasions when referees have received threatening letters, letters with razor blades contained in them
Former referee Kenny Clark
"Match officials' performances are analysed far more than the players' performances are. We seem to expect match officials to produce perfection in games where we don't expect that of players."
Regan's comments within the next few days should shed more light on why Craven decided to resign. But Clark fears that officials are more likely to be abused now than a decade ago.
"Now is worse than it was, say, 10 years ago," he added.
"You get cat-calls in the street, you'll get abusive phone calls, there have been occasions when referees have received threatening letters, letters with razor blades contained in them, and we're aware of referees having windows smashed in their homes.
"I remember when I was on the ferry to Arran and I was subjected to verbal abuse by someone even although I had my eight-year-old son at my side.
"That is by no means unusual for referees these days."
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