Ritchie damaged ankle ligaments in Newcastle's Carabao Cup second-round defeat against Leicester earlier this month following a brutal challenge by Hamza Choudhury.
“I think that's better news. With Matt, the good thing is it's an impact injury. If there's anything that an injury picks up on is impact. We know what it is.
“If it's muscles, it's always a bit of a problem and ligaments and things like that but he's out on the grass and the progress he's made in two weeks is quite remarkable. I think it could be good news for all of us.
“He doesn't look as if he'll be eight weeks I wouldn't think. The way he is at the minute - we don't put timescales on these things - but closer to four or five weeks might be better."