Kisnorbo has been out of action for a year after rapturing his Achilles during the clash with Millwall last March.
The Australian’s contract with Leeds is set to expire at the end of the season.
“He’s doing his rehab and a bit of running here and there,” Grayson told the Yorkshire Evening Post.
“But at the back of our minds we’ve ruled him out for the rest of the season.
“That’s not to say that he won’t get back, but we don’t want to rush him. It would be a bonus for us if he plays any football.
“He’s been out for so long that you get complications along the way if you’re not careful, or if you rush him back. For the sake of a few weeks, you might as well leave it.”