Bolton have fined and disciplined midfielder Liam Trotter and defender David Wheater for making an offensive gesture ahead of their defeat at Brentford on Tuesday night.
The players were also warned about their future conduct after they were caught on camera sticking their middle fingers up as they walked into Griffin Park prior to the match.
A club statement read: "Bolton Wanderers takes the conduct of its players and staff extremely seriously and will not tolerate such behaviour.
"The club would like to apologise for any offence caused by the incident."
Trotter later offered his apologies for the incident.
He told the Bolton News: "I apologise wholeheartedly - it wasn't anything aimed at the fans or the club.
"It was a silly prank, but unfortunately it went out live which we didn't know about.
"But it shouldn't have happened and I accept that we have to be better than that."
Bolton's 3-1 defeat pushed them another step closer to relegation, which will be confirmed if they lose to Derby at the weekend.