Two seasons on loan at Watford followed by a knee operation last summer have prevented the 24-year-old from making a competitive Reds appearance.
"I'm getting there," Foster told Manchester United Radio. "It's been about four and a half months now since I've had the operation but things are going really well.
"I've stepped up my training and I'm doing some work outside, a bit of fitness work, running and the odd bit of goalkeeping too."
Like any player waylaid by a serious injury, Ben's season has been one of utter frustration thus far, but he has taken heart from being able to take on more exercise of late.
"It's been frustrating because you're just stuck in the gym a lot," he said. "But now I've hit that point where I can step up my training it's a bit more enjoyable now.
"I think it will be mid-to-late February until I'm able to play again."