Coid was expected to return today for a further month after leaving the Millers early during his spell in January due to a knee injury.
Earlier Moore had wrapped up a deal to sign Callum Kennedy from Swindon Town after yesterdays swoop for Omar Daley from Bradford, with Kevin Ellison moving the other way.
But Coid declared himself unavailable for tomorrow's game, meaning the Millers may look to do something later next week in order not to waste any of the 93 day loan period.