The centre-back missed Arsenal's Premier League defeat at Manchester United on Sunday due to illness and he will not feature for his country in Milan.
However, Germany coach Joachim Low revealed that the former Werder Bremen man could play at Wembley on Tuesday.
"Per Mertesacker will remain in London and will join us when we are there for the game," said Low, who will take charge of his country for the 100th time on Friday.
"I don't think the players are thinking about it yet, I have always tried to consider clubs in my decisions but I do not want anyone to come to me and tell me to rest them on Friday or Tuesday," he added.
"I have told them there are not many games left until the World Cup. If someone thinks they are automatically picked then they are wrong. I demand full speed ahead from everyone. We've got a high level squad and there are no free passes to Brazil."
"It is part of our job to build up players who can fill gaps," he added.
"Obviously, it is a pity that Mario and Miro are out but I do not see a problem. For me, January is the cut-off date.
"If a player starts the new year normally after completing winter training and then plays through then I am certain he will join us in good form."
