The pair posed for picture of themselves while drinking on a rooftop before posting it on image sharing website Instagram on Monday night – just a day after the pair had featured in the club’s 32-10 defeat at Penrith.
“The club has strong policies in place and breaches of these policies are taken very seriously,” Raiders coach David Furner said in a statement.
“We have stood both Josh and Blake down for breaches of these policies and will determine punishment once we have concluded our investigations.”
Dugan meanwhile took to Twitter to express his remorse.
“I apologize to my team mates and the fans but this is personal and needs to be sorted out as soon as possible for me to move forward,” he tweeted, adding later: “This goes beyond the drinking while injured. Yes I’ve broken team rules but for me it goes deeper and I plan on sorting it out.”
Edrick Lee moves into the vacant wing spot.
Shaun Fensom has been named despite suffering a wrist injury against the Panthers on Sunday, with medical reports clearing him of any serious injury.