Injury blow for Sunderland defender Brown
The former Manchester United man sustained a knee injury during Sunday’s FA Cup draw with Middlesbrough.
O’Neill admitted he feared the 32-year-old would be forced to sit out the remainder of the season.
However, scans have revealed that the problem is not as serious as initially feared.
"We don't think he needs the operation but you are looking at probably about eight weeks before he is back," said O'Neill
"But, at one stage, it looked like a season-ending injury."
Brown is not expected to feature again for the resurgent Black Cats until April at the earliest.
By Ben McAleer