The Scottish Professional Football League has responded to criticism of its postponement policy by insisting that sporting fairness could be undermined if it failed to administer the rules as agreed.
League bosses also warned that more clubs would have to play with makeshift squads if the season was to be completed.
Dundee boss James McPake accused the SPFL decision-makers of putting players and families from both his club and Aberdeen at risk by refusing a request to postpone their St Stephen's Day trip to Pittodrie.
Dundee only had four substitutes stripped — two goalkeepers, one 17-year-old and 40-year-old assistant manager Dave Mackay, who was registered as a player after the club lost six players to Covid-19 issues on the morning of the game.
St Mirren manager Jim Goodwin recommended to his board that they refuse to play against Celtic last week after the club failed to get two matches postponed.
His chairman John Needham later called for a "judicious application of the rules" to take account of new self-isolation rules affecting household contacts.
However, SPFL director of operations Calum Beattie pointed out that the policy for postponing games was finalised after consultation with clubs and “provides certainty and consistency on the criteria”.
Beattie added: “The SPFL has repeatedly demonstrated that we will postpone matches when the criteria is met — with 10 league matches this season postponed already.
“While we have enormous sympathies for any club which is unable to field its strongest team as a result of Covid-19, those calling for the policy to be changed midway through the season may not have considered the wider implications.
“Failure to administer the policy consistently could lead to clubs choosing not to fulfil specific fixtures, which would have massive implications for sporting fairness, increase pressure on other clubs and threaten the ability to complete the season.
“It is an essential cornerstone of the game that scheduled fixtures must be played when teams fulfil the necessary criteria.
“Failure to do so would undermine the integrity of the league, threaten completion of the season and would certainly cause far more problems than it would solve.”
The Premiership winter break was brought forward because of limits on attendances but the three lower leagues are continuing as scheduled.
