Constantly low ratings for a player

[sincity]

Hello, everyone!
I want to ask you for some advice. I recently bought from an auction a 4 star/almost 5/, 26 old, DMC player and his last games' ratings are as follows: 5, 4, 4, 5, 5, 5, 5 /in the three tournaments/. What' s the matter? His moral is always excellent and his condition too, but he keeps producing those low ratings. So, what do you do in these cases? Is there any proven "cure" for this "condition" or i simply should sell the guy straight away till the market is still hot. Do you think that this low numbers could be changed this season somehow? Or maybe next season. I don't mind keeping him till next season, if there is a chance that his ratings will improve. I''ve never played him out of position and unfortunately he IS my only DMC at the moment. So, what's your advice. I've never seen such a string of low ratings and i am a level 3 manager now.