Neil Warnock's side, top of the npower Championship, need just a point from Saturday's visit to Watford to secure their return to the top flight after a 15-year absence.
However, the FA will next week rule on seven breaches of their regulations over the signing of Argentine midfielder Alejandro Faurlin.
Rangers have denied the charges and a four-man panel will meet next Tuesday with the result of the hearing expected on Friday - the day before the end of the Championship season.
A points deduction could see them drop out of the automatic promotion places and throw the play-offs into chaos if the club appeal against the decision.
The FA said they will not comment until the charges are resolved and Rangers have issued a statement along the same lines.
It read: "The club... will not make any further statement as both the club and the Football Association agreed to make no comment on this matter until after the hearing."
Source: PA
