Yeah, He could have been playing McNair at RB all these weeks or Blind at LB and moved Carrick to cb.Yes, plus Van Gaal deliberately reduced the size of the squad precisely because he prefers to call on youngsters to fill gaps rather than having a lot of fringe senior players just sitting around waiting for injuries. Obviously he couldn't have predicted the depth of this injury crisis but nonetheless playing all these kids hasn't been forced on him anywhere near as much as people are suggesting.
I think he deserves credit for trusting the youngsters and giving them a shot when many other managers would have tried to improvise with new tactics or play people out of position