Shaw suffered the horrendous injury after being on the receiving end of a tackle from Hector Moreno in the Champions League clash at PSV Eindhoven in September.
Man United are preparing for the reverse fixture at Old Trafford on Wednesday and van Gaal admitted Shaw’s injury came as a huge blow.
“I think the first match was very disappointing, not only because of the result but because of the loss of Luke Shaw,” van Gaal said.
“For us he is a very important player and I said in advance already he would be the revelation of the season and he was on his way to do that.
Asked about the defender’s four days off, van Gaal added: “Shaw was fed up with the daily routine and I saw why he was fed up – maybe because it was PSV.”
Shaw will face many more challenges as he continues to recover from what was a horrific injury.
The medical staff at United seem to be taking good care of the youngster – he has been seen out and about on the streets of Manchester in recent weeks – but he still has a long way to go. He will need the support of van Gaal and everyone associated with United if he is to come back stronger.