Everybody on here expects to buy a scout and he will work miracles for the team!, in the 7 seasons ive played this and bought scouts NONE of them have performed like that EVERY SEASON!, sure some do well straight away and others mediocre but they all come good at sometime if not this season but the next! so Im quite happy with that, there could be many factors or none at all as to why this is but thats the way its been for me since I played this game!, I dont buy tokens and I dont buy lots of green booster packs to power train like some of you, I just train normaly once sometimes twice a day and find this adequate for the way I play and it gets the results I need!, players ratings vary from game to game, I usually find at least one player stands out with ratings in a season then next year he might be average!.
You could list loads of ideas like condition, age, training, resting, injuries, any number of things but you just have to take the good with the bad!.