Rugby League side Castleford Tigers have launched legal proceedings against the Sale Sharks and their new recruit Denny Solomona.
Castleford's star player left the club while still having two years left on his contract. The Tigers will now sue Solomona for damages.
Steve Gill, Castleford Tigers chief executive officer, said in a statement that involving legal action was a last resort.
"In August this year we made it very clear to Solomona and to Sale Sharks that there was an unbreakable contract in place until the end of season 2018 with no basis whatsoever for either ourselves or Solomona to depart from each other's mutual obligations," he said. "The idea of losing the player was not welcomed by us and we have repeatedly told Sale Sharks that it would be impermissible for them to talk to Solomona let alone sign him. Clear unequivocal warnings have clearly been disregarded.
"Unfortunately we are not privy to what has happened over the last three months between Solomona and his agent but on the back of losing the player in the circumstances described and now announced by Sale Sharks we confirm that today we have issued Proceedings out of the High Court in Leeds for damages against Denny Solomona for breach of contract (dated 20 November 2015) and for damages including exemplary damages against Sale Sharks Ltd and Andrew Clarke (Solomona's agent) for inducing breach of the said contract.
"The proceedings have been issued as a last resort having failed over the last couple of weeks to try and resolve matters without the formality of court proceedings. We have confidence that the legal system will bring out all of the facts and the truth. We are fighting this not just for Castleford Tigers but also for the integrity of all sports including of course Rugby Union clubs. Our belief is that all contracts are sacrosanct in professional and amateur sports."
Sale Sharks director of rugby Steve Diamond, however, believes Sale have done nothing wrong.
"Denny came available late summer, so we went down the correct avenues to secure his signing," Diamond told the Sale Sharks website.
"I think the legal case is in the hand of his representatives, both sets of lawyers are talking and I'm pretty sure an outcome will come."
"I don't think we've done anything wrong at all to be honest," he added. "Players have agents and they put the players up in the marketplace. Let's get it straight: there were other clubs in for Denny and there were at least two rugby union clubs I know of that were in the market to sign him.
"There are two sides to all stories, and I can say from day one, that Sale have acted in the best interests of Sale Sharks, and done everything legitimately by the book so when people do sit down round a table, and they agree on what needs to be agreed, that'll come out in the wash.
"I understand Castleford's perspective, they are a fantastic old club like Sale are. I had three players leave me in the summer, but that's the way it is. You've got to look at the next best kid in your academy, or who is available.
"If you look at our lads here, it's no different to any environment from any other club, it's a hardworking environment, they have a go, if they aren't good enough they get moved on, if they are good enough, they get an opportunity – that's how I run it. What I never wanted to happen was to get dragged into the mud, a Union versus League battle, it's not. A player, who is a good player, became available and he'll fit into what we're doing over the next few years, that's exactly how it's been, and the legal ramifications I'm pretty sure it'll be resolved."