The Londoners face the Bundesliga giants in the Champions League on Tuesday.
He said: “I am not going to go away from home and play 4-4-2 as you will get opened up.
“We go to Germany and they play with a diamond, and so they will have four players in the middle of the park.
“We have two in there and will run around chasing shadows as they pop it around. So we will have to look at that.”
He added: “At home, I am 90 per cent certain I will play with two strikers. But away from home, it will be different.”