The Germany keeper is hoping that his team-mate is fit in time for their first World Cup match but says he is prepared to step in whenever needed
The Bayern Munich No.1 has been struggling with a shoulder problem ahead of the tournament in Brazil, having picked up the knock in the DFB-Pokal final win over Borussia Dortmund.
The BVB shot-stopper is expected to be his deputy at the tournament but the 33-year-old is still hoping that his international team-mate recovers.
"I'll be there when I'm needed," he told reporters.
"But I don't want it to be at the expense of Manuel Neuer. If I can help Manuel get fit, I will do it. I'm keeping my fingers crossed that he will recover in time to face Portugal."
Germany kick off their World Cup campaign on June 16 against Paulo Bento's side in Salvador before games against Ghana and USA.