Katich kickstarted Australia's fightback with 43 as the home side, set 375 to make England bat again, finished the fourth day on 238 for four in Adelaide.
The left-hander was clearly suffering with an Achilles injury which restricted his mobility in the field and, when Australia began to bat, he soldiered on and hobbled between wickets.
"I'm not sure the extent of the injury but it doesn't look good," said Hussey.
Katich produced some stunning shots off one foot to rack up six boundaries before he was eventually dismissed by England spinner Graeme Swann.
Hussey added: "It was an absolutely inspirational performance really. He's willing to show that he'll fight all the way, even though he is on one leg. I thought he played really well considering he was obviously in a lot of pain. I even asked Ricky (Ponting] if he wanted me to open the batting and Kato said 'Nup'. (He said] 'it's my job, I've got to do it'. I've known Kato a long time and I don't expect anything less."
Meanwhile, former Australia batsman Brad Hodge reckons world cricket is enjoying his homeland's fall from grace. "We're copping a bit of a hiding at the moment," Hodge said of the Ashes after his third Twenty20 match for the Hamilton-based Northern Knights in New Zealand. "It's probably something that people in world cricket are happy about. It's a long series, but it's going to be hard work for the guys, I reckon."
Australia are struggling to replace Glenn McGrath, Shane Warne, Adam Gilchrist, Mathew Hayden and Justin Langer. Add Brett Lee's injury problems into the mix and the side's dominant core has been uprooted. "You take four or six of your best players out of your side, you're going to struggle," Hodge said.