No firm decision has been taken on the hearing, which was arranged for Tuesday and was to be chaired by Lord Nimmo Smith. However, with McKenzie unable to attend, it is likely to be postponed.
The hearing is due to hear evidence about Rangers' use of EBTs from 2001 to 2010 and whether or not any payments to players should have been registered in their contracts.
McKenzie's initial investigations convinced the SPL that there is a prima facie case against the Ibrox club, although Charles Green, the Rangers chief executive, said they would boycott the commission's investigation.
The SPL's investigation was launched on March 5 to determine whether or not all payments made to Rangers players in respect of their earnings from football were declared, which is required by the Scottish Football Association rules.
However, Green said that "neither the SPL, nor its commission, has any legal power or authority over the club because it is not in the SPL".
If Rangers were to be found guilty, the commission can choose from a number of sanctions. However, during negotiations over Rangers' SFA membership licence last summer, individuals within the SPL wanted Rangers to agree to be stripped of the titles the club won from 2001 to 2010, which they have refused.