Unai Emery has named a strong squad for Thursday evening's Europa League clash against Sporting CP - but what formation will he adopt.
The Spaniard has named a back four in all but one of his games in charge of us - when we beat Qarabag 3-0 in Baku last month - but could he do so again in Lisbon?
"Now we are finding the best combination, the best tactical idea so we can do our best performance and sometimes, some matches they are a very good moment to try different options," Emery said.
"[Against Sporting] is not the best for us because our composition with the players tomorrow I think we are going to continue tactically how usually we are doing but for the next matches it could be a possibility to do that.