Chris Coleman is likely to move away from playing five defenders against Brentford but insists the system has not been the primary cause of poor recent results.
The Black Cats have shipped eight goals in their last three matches, picking up just one point in the process.
A shift to 4-4-2 produced a much better performance in the second half at Ashton Gate, leading many supporters to call for a change ahead of Saturday’s crucial game.
Coleman said: “Possibly [players more comfortable in 4-4-2]. But we didn’t play 4-4-2 when be beat Fulham and Hull, when we go to Wolves and get a point. The results we’ve got have not been in that formation.
“Now I’m not saying we got those results because of the other formation, I’m saying it is because of the mentality we’ve had in those games. We can’t use it as an excuse.
“It doesn’t take a rocket scientist to see I could change it because the response was good at Bristol City, but we can’t have any excuses.
“It only works one way though. When you lose five on the spin people don’t say, ‘why not go to a back three?’ People never say that, it’s always the other way round.
“I don’t think it is about formations, it is about your state of mind. We went with a certain formation here because we hadn’t had any clean sheets, then we got five in 10 or 11. Now we haven’t had one for a while, and we struggled for goals.”
Coleman has called on his players to relish the pressure of such a crucial home game, with Brentford boss Dean Smith admitting that he will look to frustrate the Sunderland support.
“We have to be careful not to overanalyze the formation, it is up to us as a group of people to make sure mentally we are right and that we match the passion of the supporters on the pitch,” Coleman said.
“If we do that, there’ll be a lot of noise and support for us.
“I know there’s huge pressure on us going into the game but I’m looking forward to it. We’ll be biting our nails but that is what we keep coming back for.”