And Wolves manager McCarthy insists Kightly will not be rushed.
He told his club's official website: "He just gets an irritation to the patella tendon in his knees so he's having ongoing treatment and he'll be out for as long as it takes.
"For me to elaborate any more I probably wouldn't do it justice, but he has to get shut of that discomfort. He's been to see a specialist in Barcelona a few times for a quite aggressive treatment, so he's doing his best to get through it and then get back.
"We're not going to rush him back."