Almunia has not played since dislocating his finger in training three weeks ago, handing Lehmann the chance to play in Arsenal's last four outings - his best run of the season.
Wenger was playing his cards close to his chest yesterday, although he did confirm he has already made up his mind about who will keep goal today.
"Come to the game and you will see. We will have a goalkeeper," quipped the Arsenal chief.
Asked whether it had been a difficult decision, he added: "No, because I have made up my mind.
"A difficult decision is if you cannot make up your mind."