Don't want to sound dumb but it is probably the best period of time for how long he is out. If he was out for six months or so we would have to buy a midfielder and carrick our third best midfielder at that time would miss the biggest part of the season and would struggle as you said to get used to Lui's system/philosophy or whatever we call it. On the other hand when he was alright he could show as a decent player(no more than that) and vG would assume he could work with him and get best out of clevlerley or possibly experiment with rooney in midfield until January when he buys Strootman..Let's not go there again.
I'm worried as it's not only 10-12 weeks out, he'll have to get fit and get used to playing in a completely new system under LvG.
So now it is the best scenario because he has got cleverley who he can turn into a decent player (anyway unplayable with Herrera IMO) and very average two players in Fellaini and Fletcher he will spot it on tour immidiately even fellaini arrives quite late and wouldn't be dependable anyway so we will have to buy someone and hopefully cope well with easy draw in first 5 fixtures. Than Carrick is back and can help the team to hold on to the top four till January when we signifiantly continue our team rebuilding with buying Strootman or whoever is availible. Hopefully someone will be because I don't see us buying two more central midfield player we desperately need before the summer tranfer window is closed just because it will be tough for vGall to offload as many as 4 or more players which are not good enough for us to make room for others. Surely he is no Moyes he will have no mercy at some stage, but it will take some time to make that decision because he has to "asses the squad he has first".