i have the same issue with Fabio Coentrao.. even his stats are slowly rising in the trainig. Sudenly he dropped his main stats by 1 point down.. I think it has something to do with the fact he can't speak english(playing premier league) and his morale is still very low even i am winning every game and he is in my first team. I hope after he gets settled, his stats are going to grow like fire, but it takes time..
(sory for my bad english)