The former Coventry City striker, who has been diagnosed with cancer, had an operation on his brain over the weekend and is making good progress.
Dr Peter Matthews, critical care consultant at ABM University NHS Trust in Swansea, said to the Press Association: "Following previous emergency surgery to relieve pressure on his brain, a pre-planned neurosurgical drainage procedure was performed at the weekend from which he has made an excellent recovery."
"In general, John is physically getting stronger and we are hopeful that he will continue to do so with the multidisciplinary care he is receiving on our critical care unit.
"We hope that he will be in a position to advance his cancer treatment (chemotherapy) as soon as possible."