Player stats declining randomly

I sometimes click on players to check his stats and I see that every stat of his has gone down 1 notch. Why is this? Is this simply because they aren't working hard enough? Whenever it happens I always give them a kick up the arse but is this the right thing to do? Is their training regime not specific enough? Is it too tough?

Injuries, age, happiness, poor trainining facilities and staff, etc. can affect this.

Is it common in youngsters?

Maybe this will happen more if you are playing at a lower level, and your facilities and youth coaches are poor. Morale should also be kept at "okay" or better. Also, see if determination attribute is above 10, if not, make senior players with high determination attribute tutor them.

It can also happen, I believe, when a player improves his "hidden" traits such as how adept he is at using both feet.

Don't worry too much, it happens all the time

It's not always a bad thing - sometimes a player loses a little bit of everything, and then when his attributes go up again, the focus is mainly on the areas hes' training hardest on, and presumably are most relevant to his position. So over time the little drops allow you to slowly reshape the attributes of a player who has lots of CA going to waste (eg. a striker who has really high ratings for marking, tackling, positioning and positioning - they won't use up as much CA as attribute points for finishing or pace, but they still use up some).

Indeed, if a player has reached his full PA, this is the only way they ever improve.

It's only really something to worry about if you see attributes going down and staying down. Normally, if you keep an eye on a player, he gets a corresponding bundle of green arrows within a month or two.