Ruan Pienaar will reluctantly leave Ulster at the end of the season with the Irish Rugby Football Union blocking a potential new contract for the Springboks scrum-half.
Pienaar, who joined Ulster in 2010, is one of the PRO12's standout players but the IRFU's "succession policy" has prevented Ulster from giving him a new deal, despite the best efforts of their operations director Bryn Cunningham and director of rugby Les Kiss.
"I am not moving on for a new adventure or for financial reasons -- I wanted to stay and I know that Ulster Rugby did everything it could to keep me in Belfast," Pienaar, 32, said. "Ulster is special to me and my family now, and I would like to thank my wife, Monique, for coming here to support me and for helping to make it home for us.
"I have many great memories of my time here and I have made some brilliant friends within rugby and outside of it. It is sad that this will be my last season as an Ulster player but I will be doing everything to ensure that we make it a successful campaign."
Ulster say "the club and the player was very keen to extend his stay in Belfast" and Kiss has described his impending departure as a "huge loss".
Kiss added: "For me, he is a fantastic player, but he is an even better person, who is much-loved by his team-mates, the staff and management, and the wider rugby community here in Ulster.
"His influence within the squad, both on and off the field, is truly remarkable; whether that is through match-winning contributions, or mentoring the promising players coming through our pathway.
"Indeed, he has played a big part in helping us to develop a large group of talented young backline players who have gone on to represent Ireland in recent years.
"He is a consummate professional and I have absolutely no doubt that he will give everything to the Ulster cause for the rest of the season. Our hope is that he will one day return to the province to continue to have a positive impact on rugby in Ulster."
David Nucifora, IRFU performance director, later clarified the governing body's position in a statement: "The IRFU recognises the contribution that Ruan Pienaar has made to Ulster Rugby over the seven year period he will have been with the club, however the IRFU informed Ulster Rugby during the 2015-16 season that it would not sanction a further extension of his contract.
"It is vital for both Ulster and Irish rugby that the province develop indigenous talent in this position and an extension of Ruan's contract would further prevent Irish qualified Ulster players from maximising their developmental potential and becoming stars for both Ulster and Ireland."