"He has started light training and has had a little touch of the ball now," says Roger Cross.
"It was quite a heavy bang for him - I think he did his medial ligaments - and it was painful.
"He is moving in the right direction but it is going to be touch and go for the weekend.
"Rob Lee is such an experienced player and up to this injury he collected he hadn't missed a day's training.
"He had played all the games as well and I think he has been outstanding for us."
Meanwhile, Roger warns that West Ham must not depend on Jermain Defoe, who came on as a substitute for England U21s in the defeat by Portugal on Tuesday, and David Connolly, who scored for Eire in a man of the match performance against Turkey, to supply all the goals this season.
"We have got to chip in with goals from other areas - that is very important; we can't rely on those two to get goals all season, that is for sure.
"I haven't seen it yet but I have read that David's was a super goal."
Comparing him with Jermain, Roger says:
"He has got similar skills and they have both scored four goals apiece so far this season; he has wonderful ability and does score spectacular goals every now and then."
And that £285,000 price tag?
"It would be a lot more than what we paid for him; at the moment it looks like a good signing but let's wait until the end of the season and we will know if it was a real bargain or not."
The visit of Reading means that one 'managerless' club will be playing another after the resignation of Alan Pardew on Wednesday late morning.