David Moyes says Robin van Persie is progressing well in his rehabilitation from injury but insists there will be no miracle recovery.
Van Persie was originally expected to be out for between four to six weeks after spraining his knee in the final moments of the 3-0 victory over Olympiacos last month.
The Dutch international scored a hat-trick in that game in earn a quarter-final tie against Bayern Munich but was subsequently ruled out of the first leg and only given a slim chance of making the second leg in the Allianz Arena.
Manchester United manager Moyes says that although Van Persie is progressing well and is expected to be back before the end of the season, he won't be fit to face Bayern.
"Robin is over in Holland having treatment and we get a daily update of exactly how he is," he said to reporters. "He's getting better.
"He's doing all of his recovery and rehab back there. He's coming on, as far as we know."
As previously mentioned, the Premier League Golden Boot winner of the last two years was originally ruled out for between four to six weeks, giving him slim hope of making the Bayern away leg next week.
However, Moyes says he has been given no inclination to believe Van Persie is nearing a return to fitness, nor is it going to be longer than six weeks.
"I was told four to six weeks by the doctors and there hasn't been any reason to tell me any more or any less time.
"We will monitor that. My hope was that we would get him back before the end of the season, that's for sure.
"The big thing is we'll be medically led. We won't push. If it's not right, we certainly would not bring him back sooner. We will totally be led by the medical team and Robin.
"Robin is a good judge of how his own body feels. It's part of how we've tried to deal with Robin through the season and giving him the understanding that he tells us how he feels. He'll be the first one to tell us how he is."
News that Van Persie won't return for the Bayern Munich game follows news that Wayne Rooney is a major doubt with a toe injury.
Rooney, who played a key role in the 1-1 draw in the first leg, is expected to miss the trip to Newcastle today and may not be fit to travel with the squad to Bavaria on Wednesday.