MILLWALL chief executive Andy Ambler has warned that the club is treading a disciplinary tightrope after Saturday's coin-throwing incident at Bournemouth.
Defender Steve Cook was hit by a pound coin thrown from the away end in the aftermath of the Cherries' fourth goal, scored by ex-Lions striker Lewis Grabban.
Earlier this season, Derby right back Adam Smith, a former Millwall loanee, was targeted by objects thrown from the Dockers Stand at The Den.
And Ambler now fears a reprisal from the Football Association, who have confirmed they are investigating the Cook incident.
He said: "However unjustly we feel we have been treated by officials, we cannot tolerate individuals throwing objects onto the pitch.
"Something is going to come [from the FA] if we are not careful – we will face a closure of certain parts of the ground or it could even be a points deduction.
"Too many incidents have occurred at our matches and it cannot continue."
An FA spokesman said: "We are aware of the incident and will be liaising with both clubs to get an understanding of exactly what happened."
It is understood Grabban's antagonistic celebration, directly in front of the travelling fans, is likely to be included in referee Lee Collins' report.
Bournemouth won the match 5-2.