Yes he did suffer from injury just when he was about to start a loan spell with QPR, scored a couple of goals for them in a pre season friendly, they got excited and then he got injured and never managed to recover from it.
But to be honest his lack of form started before that at the end of last season....
Personally, i still think he can make it, time is on his side. A final descision won't be made on him for another 2 or 3 years at least. But the next year is going to be crucial for him....