Northampton lock Christian Day will retire from professional rugby at the end of this season.
Saints' announcement also said that Day, 34, will become full-time player liaison officer with the Rugby Players' Association from July.
Day, who joined Northampton 10 years ago, was RPA chairman from 2014 to 2017, and vice-chairman this season.
He made more than 200 appearances for Northampton and was players' player of the season when they won the Premiership title and European Challenge Cup in 2014.
"After 17 years of professional rugby, time has caught up with me, but I am extremely proud to have contributed so much at Franklin's Gardens in 10 seasons as a Saint," he said.
"I have been battling an injury for some time which will unfortunately prevent me from playing in this season's remaining fixtures."
RPA chief executive Damian Hopley added: "This is a significant appointment for both the RPA and the players we represent, and it's fantastic to welcome Christian to join our team.
"In his eight years as an RPA player representative and board member, Christian has proven himself an effective and respected leader both on and off the field."