Joachim Low has told injured Bayern Munich goalkeeper Manuel Neuer he will need to be playing to make it into Germany's World Cup squad, though he has been assured of a return before the season's conclusion.

Neuer has endured a difficult 12 months, having broken his foot three times and managed just three Bundesliga displays this term.

Bayern have been particularly careful managing Neuer's comeback, as they seek to avoid another recurrence of the injury.

He is in the final stages of his rehabilitation ahead of a potential April return, but any setbacks might prove costly for him as Low says he needs to be playing if he is to be involved in the World Cup.

"If a player plays no role in the preparation, it is difficult to nominate him," Low told reporters on Thursday ahead of Friday's friendly with Spain.

"When Manuel came to us on Tuesday, together with Andy Kopke [coach] and Dr. [Hans-Wilhelm] Muller-Wohlfahrt [we] had a long conversation with him. Manuel is absolutely on schedule. It is planned that he will still play at Bayern this season.

"The doctor has assured me that the condition of his scar and the growing together of the bones are absolutely fine and look very good.

"However, at the current stage he is not allowed to [train] at maximum, he is currently training at 90 per cent and wants to increase to 100 per cent this week so that he is fully resilient.

"Then he can still get the necessary security in the training sessions. I assume and am very optimistic that Manuel will be present at the World Cup."

Even if Neuer does suffer a setback and has to miss the tournament, Germany will be in good hands between the posts, as Barcelona's Marc Andre ter Stegen will be waiting to take his place.

And Low was full of praise for Ter Stegen, who he believes has matured in LaLiga.

"He has developed very, very well," Low added. "His first games in the national team were a bit mixed. But in the last few years he was very, very good. He played a major role in the Confederations Cup.

"He has grown up in Barcelona, he plays well. As a goalkeeper he is very, very calm, relaxed and focused.

"You can feel his charisma. He has gone through a maturing process at Barcelona. He has become a personality who has a very good standing with us in the team.

"One senses with him that he puts a very strong emphasis on the performance and that also shows continuously."