Manuel Neuer and Jerome Boateng face a race against time to prove their fitness for Germany's World Cup campaign, but Mats Hummels feels the reigning champions are able to replace the key duo.

Bayern Munich captain Neuer has been out of action since September due to a broken foot, while his club colleague Boateng suffered a hamstring injury in the first leg of the Champions League semi-finals against Real Madrid in April.  

Goalkeeper Neuer has returned to full training in recent weeks, but centre-back Boateng is still working individually during the national team's pre-tournament training camp. 

Addressing a news conference on Tuesday, fellow Bayern man Hummels spoke of the pair's importance to Die Mannschaft, but also expressed his faith in the squad's strength in depth.

"Both players are terrific, potentially the best [in their position]," he said.

"Not having them on the field is a negative. But at the same time, it allows other players to step up and play that role. The potential for them to [recover in time to] play is still there."

Marc-Andre ter Stegen of Barcelona appears the prime candidate to take over from Neuer should he fail to recover, and Chelsea centre-back Antonio Rudiger looms as a possible replacement for Boateng, despite an inconsistent campaign at club level. 

Hummels, though, was reluctant to identify the specific options at the disposal of head coach Joachim Low. 

"There are plenty of players on the roster who can step up and fill those gaps," he said.

"Whoever is in the best form and playing their best at the moment will get a chance to prove it in the right moment. I can't say any more than that."

Germany will arrive at the tournament in Russia as both the holders and one of the favourites, but Hummels is not concerned about the potential for distraction amid the intense scrutiny that will accompany them.

"Focus is not a problem for the team," he said.

"We have a system to fall back on, we have belief, we know our roles and how things should progress. Security and confidence breeds focus. I don't believe we will struggle in that department.    

"Although mental fatigue [after the domestic season] can be an issue, I don't think that is the situation. It's about sticking to what you do. If you conquer an obstacle you can take many more challenges head on."