Poyet's January dealings will be decided by Sunderland's next few games

Having assessed the strengths and weaknesses of his squad since replacing Paolo Di Canio almost two months ago, Poyet is determined to make changes in the January transfer window.

However, the extent of his restructuring will depend on the number of players he feels he needs to replace, and that total continues to fluctuate from one week to the next.

Last weekend's performance at Aston Villa suggested that his training-ground instructions are getting through, and if the improvement continues against Chelsea this evening, the Sunderland manager will be tempted to keep his January tinkering to a minimum.

However, if his players lapse into bad habits against his former employers, and in their remaining pre-Christmas matches against Tottenham, West Ham and Norwich, his transfer shake-up could be more extreme.

“I have an idea of what I want to do in January,” said Poyet. “But there is time for that to change. It is not like I am not going to bring anyone in, I will. But depending on the next two or three weeks, it could change the number I make. If we don't keep improving, we need a bigger change.

“When you are coming close to January, you are thinking what you need to do. The more the team improves, the fewer changes you will see. But there is a limit – I cannot go until December 28 waiting to see positive signs.

“The next few weeks are important, deciding if we need two new players or five. It depends on the players, but it is nice to see that certain things we have worked on have sunk in.

“If I had not see what I saw on Saturday, I would be more worried. The way we trained and planned the game, there were encouraging signs.”

The goalless draw halted a losing run of away games that had stretched back to the second weekend of the season, but Sunderland's home form under Poyet has been much more positive.

Last month's Capital One Cup win over Southampton sandwiched Premier League victories over Newcastle and Manchester City, with the latter game providing one of the shocks of the season.

It would be another huge surprise if Sunderland were to see off Chelsea tonight, although recent evidence suggests it would be wrong to make too many assumptions about matches between teams at opposite ends of the table.

“We know they (Chelsea) are one of the best teams in the country, but we all believe in what we are doing,” said Poyet, who scored 49 goals in 145 appearances as a Chelsea player. “Can we beat them? I definitely believe it is possible, especially after beating Manchester City at home.

“That shows you there is a way, and hopefully we will find it. Prior to Aston Villa, I thought we were either doing well in defence or attack. In terms of balance, that was the best game, and we need to put the whole game together again.”

Sunderland will be boosted by the availability of John O'Shea, who trained without problem yesterday despite appearing to injure his groin in the closing stages at Villa Park.

“He is not a risk because he has trained and felt completely all right,” said Poyet. “It was a happy surprise because of course we were paying attention to him.

“He didn't feel that he had pulled a muscle, it was just a strange feeling something wasn't right at that time. But he recovered well and trained without any problems. As long as nothing goes wrong, he will be there.”