London - Australia international Rob Horne has been forced to retire from professional rugby union at the age of just 28 following a career-ending arm injury, the centre's English Premiership club Northampton announced Saturday.
Northampton's statement came just a week after Horne suffered nerve damage to his right arm in the opening minute of the Saints' 27-21 win away to Leicester last Saturday.
He then required several minutes of on-field treatment before being carried off and undergoing tests by neurological specialists at London's Royal National Orthopaedic Hospital.
"This is absolutely tragic news and has been devastating for every member of the squad and staff here," said Northampton interim head coach Alan Dickens.
"All our thoughts are of course with Rob and his family at this time.
"Rob is not only a world-class rugby player, but he is an exceptional man."
Dickens added: "He is a hugely-respected and popular member of the dressing room, and this will be an enormous loss to Saints, both from a rugby and a personal perspective.
"Even though he had only been here for one season, I am sure he was destined to become a club legend and, like everyone, I am deeply saddened that his career has been prematurely ended in this way."
Horne joined Saints in pre-season from the Sydney-based Super Rugby side the Waratahs. He won 34 Test caps, playing in two World Cups, and represented the Wallabies against the 2013 British and Irish Lions.
He scored eight tries in 21 games for Northampton, and captained them in the Leicester match.
Saints chief executive Mark Darbon added: "Rob has been the ultimate professional in his time at Franklin's Gardens, and shone on the pitch in what has been a difficult season for Saints.
"This news has shaken everyone at the club, and I am sure all of our supporters will join us in sending our best wishes to Rob, his wife Simone and their two young children.
"Rob will always be a part of the Saints family, and we will, of course, do everything we can to help him through his rehabilitation and transition in to the next stage of his life.
"Rob has asked me to pass on his deepest gratitude for all of the messages of support he and his family have received, but would now like everyone to respect his privacy while they deal with this news."