Young, an England international, was injured during United's 5-0 thrashing of Fulham on Wednesday.
"It's not so good for Ashley Young," Ferguson told a news conference. "We're still waiting on some of the bleeding to go away, which is quite extensive at the moment. It was a sore one so he'll be out for a few weeks."
There was better news about Phil Jones who was caught in the face by an elbow from Fulham's Clint Dempsey during the match and came off in the 20th minute.
Ferguson said X-rays showed the versatile defender should be fit for United's Premier League clash against Wigan on Monday.
"He has some swelling in his jaw but there's no break, no fracture, which is good news," Ferguson said.
"We feared the worst because he lost his vision a bit in that period when he came back on to the field. Thankfully it's good news."
Brazilian defender Rafael da Silva is also expected to return from long-term injury but Ferguson will be without midfielders Tom Cleverley and Anderson.
Earlier this month, United lost captain Nemanja Vidic for the season with a ruptured cruciate knee ligament and midfielder Darren Fletcher announced an extended break from the game with a chronic bowel condition.
"It's not an easy spell for us but we just have to get on with it. The squad has handled the situation quite well," Ferguson said.
"The form has been really good and I'm pleased with that. We're scoring goals again, which is terrific."
‘The pure simplicity of the way Slot has managed the squad is probably the biggest thing I could say about him. It’s not broken, so let’s get on with it’: Liverpool legend full of admiration for Jurgen Klopp's successor at Anfield
‘I trained at Spurs and thought they’d give me a chance. But I received a letter thanking me but saying they didn’t think I was good enough – I was gutted’: How Tottenham missed out on signing Wales legend John Toshack
