The 25-year-old midfielder suffered the problem on the eve of his side´s Barclays Premier League defeat at Wigan on August 18 and it was initially thought he would only be out for six weeks.
But Keane told the club´s official website: "It looks as though Deano will need surgery in a couple of weeks. It looks like it´s a cruciate so that would rule him out for six or seven months. It´s been a bad day. It´s a bitter blow. We are missing his leadership qualities and his presence."
Copyright (c) PA Sport 2007, All Rights Reserved.
Do YOU want to write for GiveMeSport? Get started today by signing-up and submitting an article HERE: https://www.givemesport.com/writeforgms