Harlequins prop Richard Villasanti has been forced to retire after failing to recover from a knee injury.
Villasanti has not been able to play a match for Harlequins
The 27-year-old Australian joined Quins in February from Cronulla following minor surgery but the club say the knee has not responded to rehabilitation.
"The club would like to commend Villa on the outstanding way he has conducted himself," said a Harlequins statement.
"It is never easy for a player with such talent not to be able to do the job he asks of himself."
The former New Zealand Warriors player, who played one Test for Australia in 2003, had surgery in Australia and passed a medical before signing for Quins.
Villasanti was expected to be available after four to six weeks but he has been unable to play a first-team game for the Super League club.
"The end of a career at such a young age is a particularly hard thing to accept," the Quins statement added. "With the support of his family, he has done so manfully. We wish him all the best in the future."