The trio were understood to have been drinking whilst eating dinner at a “Western Sydney venue”, according to club management.
But the Tigers’ policy does not allow for the consumption of alcohol whilst players are rehabilitating from injury.
All three players have been fined and censured for their actions.
Fulton (shoulder), Ryan (groin) and Gibbs (ankle) all missed the Tigers’ victory over Canberra on Saturday.
Wests Tigers Chief Executive Stephen Humphreys said:
“The players understand that they have let themselves and their team mates down with a poor decision on this occasion.
“They have apologised to their team mates and have been fined for the breach of team protocols.
“The players are now focussed on their rehabilitation programs and are 100% committed to returning to the field as soon as possible.”