Dane Casper Ankergren is set to be given a first-team run after regular Shane Higgs picked up a thigh strain in their weekend win at MK Dons.
However, with Alan Martin on loan at Accrington, Grayson has no experienced back-up to Ankergren, who will be given the nod against Carlisle.
Grayson was keen to bring in some cover in the unlikely event Ankergren picked up a knock before Higgs returns to full fitness.
Ankergren had been Leeds' number one prior to the summer arrival of Higgs, who had performed well after joining for free from Cheltenham.
England Under-21 international Fielding has League One experience after spending three months with Northampton Town last season.
Leeds 1/3, Draw 7/2, Carlisle 9/1