Cornish Pirates back-row Alex Cheesman has been forced to retire at the age of 29 because of repeated concussions.
Cheesman has still not fully recovered from the last of a series of concussions he suffered while playing for the Championship club last season.
He played 122 games for the Penzance-based side in six seasons, having also had spells at Sale and Wasps' academy.
"I can think of no better club to end my career," said Cheesman, who played in three Varsity games for Oxford.
"Ever since joining as a fresh-faced 23-year-old back in 2012, I've been amazed by the kindness, generosity and passion of the Cornish people and I feel very privileged to have been able to play in front of them and to have shared so many memories with them too," he added to the club website.