Andrew already said why man, in players database theres a row that indicate if the player will improve or not, or even decrease his skills over your dinasty seasons.. some players has hight percentage of improving over the seasons, others not...
i will give u an easy and clear example:
Chris Webber is an star player and excellent Power Foward, one of NBA´s best PF... hes 30 years old now, do u think that when he get 37-8 years old he will still running all around the court, dunking and launghning at his guard?
take a break and a time to analisys some good players who has already decreased their gameplay in real life and u will understand why ur players are decreasing in ur Dinasty game...
and all of us know that the major indicator to know if a player will decrease is his
age.. humm thats all
ps.: take a look on how LeBron, Nenê, Yao Ming and some other good rookie/young players improved in ur dinasty game...
