I agree he's been great but I'm not sure he's been under rated. If you look at the reaction on here and the number of people saying he was player of the season so far, I think a lot of people realise how good he's been.
I think he has been underrated at the time. He has put in some strong performances and gotten a lot of low marks on the match day ratings thread, I think people have started to realise more recently that he has been performing better than had been acknowledged, and now they understand more what a loss he is.