The Black Cats have been on the end of humbling defeats to Leicester and Norwich.
The Black Cats have conceded a total of seven goals so far in defeats to Leicester City and Norwich City and have come in for a lot of criticism for the manner of the defeats.
This weekend's game against Swansea City could see changes to their line-up, with Sebastian Coates and Younes Kaboul struggling to form that effective partnership that the Sunderland boss will have hoped for.
He's quoted in the Sunderland Echo, saying: “I didn’t want to change the back-line already after one game.
“But at the moment, there are players playing who I can’t understand why they are playing that way.
“I cannot understand it, honestly."
That in itself should be a worry for Sunderland but it should bring about changes to the starting XI. If there are to be changes made to the heart of the defence then John O'Shea is poised to make a return to the side.
There needs to be a lot of work on the training ground and analysis from Advocaat of where the side is going wrong at the back so they can turn around this worrying start to the season.
At the weekend they are coming up against a very difficult side in Swansea City, who will take great heart from their start to the season which saw them get a draw at Stamford Bridge which was followed by a win over Newcastle United.
The report says there was a team meeting to try and establish what exactly has gone wrong so far. Advocaat will hope that is the starting point and they can begin to turn things around, and quickly.