Rangers are continuing their battle against the Scottish Football Association in the Court of Session in Edinburgh.
The club launched an application for a judicial review against a 12-month signing embargo on Friday after losing an SFA appeal the previous week.
The embargo was imposed as punishment for bringing football into disrepute by failing to pay £13m in tax last season.
The club is arguing that the SFA judicial panel did not have the power to impose the sanction, specifically a ban on registering players aged 18 and over, as it was not explicitly laid down in its rules.
However, the SFA articles of association include a clause that a judicial panel can implement any sanctions it deems appropriate.
The panel, which was chaired by a QC, stated that the club`s actions were second only to match-fixing in their seriousness and that it had considered expelling or suspending Rangers from the SFA.
The original decision was upheld by an appeal tribunal chaired by serving judge Lord Carloway.
The next conventional step for Rangers was to take its case to the Court of Arbitration for Sport in Switzerland but it took the controversial move of legal action, which is prohibited under FIFA rules.
The case is being presented with the help of the Rangers Fans Fighting Fund.