Hammersmith and Fulham Police continue to liaise with the FA and Chelsea in an attempt to identify the fan who threw the coin at Drogba as he celebrated scoring his goal. So far, no arrest has been made.
The police are studying CCTV from inside Stamford Bridge as well as reviewing Sky's coverage of the game. They are also in contact with Burnley Police.
Leaflets were handed to Burnley fans before Saturday's game at Queens Park Rangers inviting anyone who witnessed the coin being thrown to come forward.
Meanwhile, Buck insisted that defender Michael Mancienne, who is in England's squad to face Germany tomorrow, has a long-term future at Chelsea.
The 20-year-old is on loan at Wolves having spent most of the previous two seasons on loan at QPR. But Buck said: "He is a very good young player and we look forward to him at some point making it into the first team.
"Unfortunately, we have lots of good players who play in the same position so in the last couple of years we've sent him out on loan to gain experience."
