Grayson told BBC Radio Leeds: "I'm still hopeful that he'll play some part this season. It's obviously dictated by the surgeons because it's a major injury, but to have Paddy back at any time will be a big boost for everybody."
Grayson added: "He's been in America doing rehab since his operation and is due back anytime. He's coming along nicely but there's no time limit on it."