"Luckily, the owner gave us a donation towards the vet's bill."
He took the cat, whom he had nicknamed Stratojet, into the Times-Age on Tuesday, with his body shaved and his wound treated.
"His fur came off all in one hit," said Mr Warren. "They had to knock him out so they could get it all off. It was full of knots. It needed a huge long comb.
"And they only discovered his wound after his fur came off. The owner didn't even know it was there."
Stratojet was also desexed for good measure and, despite being groggy from his operation, seemed to have no problems posing for the Times-Age camera.
Mr Warren said he was glad that Stratojet's owner surrendered him when it was clear she was unable to care for a pet.
"She had some personal things going on, and she admitted she just couldn't look after this animal," he said.
"We were fortunate we were in the position to take him. He's an otherwise-healthy cat."
Once he has recovered from his surgery and haircut, Stratojet will be available for adoption, hopefully by this weekend.
Mr Warren predicts he will get snatched up in no time.
"Most ginger cats go pretty quickly," he said. "For now, we're just keeping an eye on him. It's a huge thing he's been through."