Aberdeen midfielder Kari Arnason could have a scan to determine the extent of a hamstring injury that would have prevented him facing St Johnstone.
Monday's match was postponed because of fog, but Dons boss Craig Brown has revealed that the Swedish defender would have missed the game.
"The hamstring injury is one which does take a bit more time than some of the others," Brown told the Dons' website.
"So we have to get it properly and carefully checked."
Brown thought that it would possibly require "a scan just to confirm the extent of the injury".
Arnason now faces a race against time to prove his fitness ahead of Aberdeen's next match, against Motherwell on 19 November.
"He wouldn't have been able to play last night, so that means we would have had two midfield players out - Rob Milsom and Arnason," said Brown.
"We are disappointed the game was postponed. But, with it being postponed, it will give both these injured players a little more time to be ready for the re-arranged fixture."
St Johnstone wanted to make use of a free weekend because of international fixtures by re-arranging the fixture for this coming Saturday.
However, with Mohamed Chalali, Josh Magennis, Peter Pawlett and Ryan Jack - suspended for the clash with Saints - all on international duty, the Dons refused the request.