The Professional Footballers' Association has said the conviction of Adam Johnson for child sex offences means it still has "much work to do" in educating players.
The 28-year-old former England and Sunderland footballer has been told he will receive a " substantial prison sentence" after he was found guilty of sexual activity with a besotted 15-year-old fan.
Johnson had already admitted a less serious charge of sexual activity with the teenager and also grooming her over social media.
The PFA, whose chief executive is Gordon Taylor, expressed its alarm on Thursday and said as a players' union it would be pushing the message to its members that footballers must not let standards of behaviour slip.
In a statement, the PFA said: "Players are role models and as such have a responsibility to behave in an appropriate way.
"It is extremely disappointing to see the damage caused by the actions of one of our members. Adam has clearly made very serious mistakes and in due course the court will determine his punishment.
"As the players' union we are very conscious of the role and responsibility of our members and we work hard to ensure they receive relevant information and important guidance regarding appropriate standards of conduct."
The PFA pointed out it has developed a training programme that has received input from groups including Rape Crisis, White Ribbon and Women's Aid, to make sure players were fully informed on issues including "sexual consent, standards of behaviour and respectful relationships in person and on social media".
The PFA statement added: "Situations such as this, unfortunately, demonstrate that this is a vital area for our focus and that there is still much work to do."
The Football Association criticised the behaviour of former England player Johnson and expressed its sympathy for his victim.
The FA said in a statement: "Adam Johnson's conduct in this case is to be condemned. Our thoughts are with the victim and her family as they look to rebuild their lives after this traumatic ordeal.
"The FA's safeguarding team spoke with the club in April 2015. Sunderland confirmed Adam Johnson did not have any roles with the club involving a position of trust with children and was not involved in their community schemes.
"The FA now awaits the sentencing hearing and the final decision of the court in this matter."