The Black Cats are on a dreadful run that has seen them win just twice in the league this season and the fixture list over the next month offers little respite.
O'Neill's side play host to Chelsea and Reading before trips to Manchester United and fellow strugglers Southampton with home clashes against Manchester City and Tottenham between Christmas and New Year.
And it does not get any easier in 2013, with a clash against Liverpool at Anfield their first fixture of the year.
But O'Neill knows that he cannot afford to let his rivals steal a march in the transfer marker and is already planning his moves for when the window re-opens in January.
He said: "We have got a really big month ahead and a lot of games - as has every side in the Premier League - so it is tough.
"But it doesn't mean that you shouldn't be thinking of looking at the January market as everybody does. All the clubs in the Premier League will be looking at it.
"If people are very active or inactive, I just don't know, but we will certainly have a look at it."