Manuel Neuer feels it is "impossible to predict" when he will be back playing again, despite offering a positive update in his recovery from a foot injury.
The Bayern Munich captain has stepped up his rehabilitation as he aims to regain full fitness following surgery on the problem last September.
Neuer revealed how he is now able to run for extended periods without pain and could be cleared to train outside as early as next week, so long as a scan reveals no new issues.
"It's been a great day, an emotional day, because I ran at 100 per cent three times for five minutes for the first time," Neuer told Bayern TV.
"I didn't feel pain in my foot; it was the same feeling in both feet. It was an important step that running went well.
"There was no reaction. The foot wasn't swollen and my muscles weren't too weak. I didn't have any tendon problems either, no problems at all.
"I'll undergo an MRT [scan on Saturday], so we'll have a close look at the pictures, as we've done continuously, to see how things are going, whether there are any warning signs.
"If things go well, I think I'll be able to run out on the training ground next week."
While admitting he is making good progress, the 32-year-old refused to be drawn over a potential date for his comeback.
"It's impossible to predict. We do have to be especially cautious," he added.
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"That's why I've only increased the load step by step. It's really important nothing happens to my foot, otherwise my career would be at risk.
"But I'm very confident regarding my foot, and that I can play again. I'm at the right level at the right time and it all comes with time. I think I'll return to full strength.
"Of course, you're impatient. Athletes are very ambitious and it hurts when you're an onlooker for such a long time."
National coach Joachim Low has stated Neuer must play before the end of the season if he wants to be considered for selection for the World Cup.