The NRL has come down hard on the Dolphins for an anti-tampering breach, fining the club $25,000 for attempting to induce centre Deine Mariner to break his contract with arch-rivals Brisbane.
Mariner's manager Dixon McIver has also been handed a warning.
Dolphins CEO Terry Reader told AAP the club was "perplexed by the breach notice and will respond in due course".
McIver told AAP he had done nothing wrong and felt "violated" by the ruling.
Under contract with Brisbane until the end of 2024, Mariner had shocked the Broncos last October when he approached the club seeking an immediate release.
Brisbane rejected the request and made a complaint to the NRL regarding the Dolphins' dealings.
AAP has been told someone called Mariner last year, not McIver, to say he would be paid a lot more money to join the Dolphins if he gained a release from his Broncos deal.
NRL rules at the time prevented any rival club from making an offer to Mariner until November 2023, while it is also illegal for teams to attempt to persuade players to break contracts.
The NRL has now completed an investigation into the matter, handing the Dolphins a breach notice with a $50,000 fine, of which 50 per cent is suspended.
"It is alleged that both the Dolphins club and the player agent contravened the NRL Playing Contract and Remuneration Rules (PCR Rules) in dealings concerning Brisbane Broncos player Deine Mariner," the NRL said in a statement.
"Specifically, the breach notice alleges a failure by the club to comply with the record keeping provisions of the PCR Rules.
"The notice proposes a $50,000 financial penalty (50 per cent suspended) for the club.
"The show cause notice issued to the Player Agent alleges a failure to comply with the player negotiation provisions of the PCR Rules and the record keeping provisions of the Agents Accreditation Scheme Rules (Scheme Rules).
"(It) proposes a 12-month suspension of the Agent's accreditation should he again breach the Scheme Rules or the PCR Rules in the next 24 months.
Both the Dolphins and McIver have until next Thursday to respond to the breach notice.
AAP has been told the Broncos have a good relationship with McIver and do not blame him for what unfolded with Mariner.
"I can't point the finger at the Dolphins for doing anything wrong and I also understand how the Broncos feel. I probably shouldn't have spoken to anyone about anything," McIver said.
"This has taken me by surprise because I have always played by the book. It feels like someone has robbed your house. You feel violated a bit.
"There is nothing for me to appeal against. I take a lot of pride in what I do.
"The way I see things is that if I am not supposedly displaying good behaviour the next 24 months I should be suspended for five years. That is the way things should be.
"I know I have not done anything wrong. I thought this whole thing was done and dusted."