The Rugby Park surface failed an early pitch inspection on Saturday.

The Scottish Premier League is writing to Kilmarnock and Motherwell to seek answers over the postponement of their weekend fixtures.

Pitch protection systems failed at Rugby Park and Fir Park and SPL secretary Iain Blair branded the situation an "embarrassment".

"We won't be able to move forward until we get all the information in," said a spokesman for the SPL.

"There has been dialogue with the clubs but that needs to be formal now."

The SPL hopes to have all its questions answered before their next board meeting on 18 December.

The criteria for top flight membership states that each club must ensure the "efficient and effective operation" of an underground heated pitch protection system.

And rule H6.6 adds that "such systems shall be fully utilised by the home club before any league match where there is a reasonable possibility of its pitch otherwise being frozen or covered in snow or ice".

Kilmarnock were unable to confirm at the weekend whether their undersoil heating was experiencing problems.

Chairman Michael Johnston issued a short statement saying the game with Aberdeen had been postponed "following a prolonged period of frost in Kilmarnock, contrary to earlier long-range weather forecasts".

Motherwell manager Mark McGhee wanted answers after their postponement against Hearts, which came despite the added protection of pitch covers.

McGhee, who called for a feasibility study into summer football, claimed Fir Park's heating system had been working but an area in one six-yard box had been frozen.

If Kilmarnock and Motherwell are found to be in breach of SPL rules, they could face sanctions, which include the possibility of a fine.

Aberdeen, whose players and fans faced a four-hour journey to get to the game, were unhappy with the timing of the Rugby Park inspection.