The Football Association are looking into Kevin Davies' comments about referee Mark Clattenburg following Bolton's goalless draw with Fulham.
The official ruled out what would have a been a winner from Davies towards the end of an uninspiring clash at the Reebok Stadium last weekend. After the game Davies suggested the referee had "something personal" against him.
An FA spokesman said: "I can confirm we have written to Kevin Davies to ask him for his observations following his media comments."
The FA will now wait for the player's response before deciding whether or not to charge him.
Davies said at the time: "When I saw who was the referee I didn't expect to get anything off him. Over the years I have never got much from him.
"There was a penalty at Old Trafford last season and he did nothing - but I got a booking.
"Numerous bookings over the years - I don't know, I have always felt there is something personal there.
"Every time he referees us, I don't expect to get anything."