I completely get that he had a bad injury and it might take some time to get over but let's call it like it is, footballers pick up these sort of injuries all the time, it's not something rare, it's something you should almost expect to happen at some point in your career,
We've had plenty down the years who have had horrific injuries and their return to the first team hasn't created as much talk and sympathy seeking as this one has. There are some players as well who continually pick up long term injuries and go through their careers barely playing any games. Luke is young, he's not injury prone despite a few fitness issues, he needs to get himself into a right state where he can perform to the level he was at the start of last season, hell even the first few games of this season.
It also seems to me that since he was criticised by Mourinho after the Watford game that was what triggered a dip in performance, which doesn't quite fit in with the injury issue, and that tells me he's been overly sensitive to the criticism. Pulling out of today's game if true is unacceptable really and shows a huge lack of character, needs to get it together because he's a top talent.