The Black Cats have made a disastrous start to the campaign, and are still looking for their first win in the Premier League.
And it seems that Dick Advocaat has decided that his favoured 4-3-3 formation is not working as effectively as he hoped, meaning he may mix things up against the Hammers.
"The gaffer is working on different things and I know he’s mentioned it,” Fletcher said. “But we’ll just have to wait and see if he does that on Saturday.”
Advocaat's 4-3-3 formation has left Sunderland's front-man isolated so far this season, with the side struggling to score goals. The North East outfit's defensive record is even worse, though, and they have conceded a staggering 16 goals in their first seven Premier League games.
It leaves Sunderland with just two points, and West Ham are not a team which they will be relishing facing.
The Hammers have been in superb form over the early part of the season, and their array of attacking talent makes them a very dangerous opponent.
As a result, Sunderland will have to be much improved if they are to get anything out of Saturday's fixture, with the pressure starting to mount at the Stadium of Light.