Does PA change over time?

Was wondering if the potential ability of a player changers depending on playing time, training and age?

ie will a young player trained with good coaches and given first team football increase his PA?

don't think this has ever been the case. PA is fixed. but CA changes obviously.

would be nice with changeable PA, but i can understand what an hassle it would be in the making of the game.

thanks RedArmy20