Cardiff Rugby can confirm Hallam Amos has suffered a high grade hamstring injury and will miss the remainder of his final season at the Arms Park.
In October, the Wales international announced his intention to retire from rugby at the end of the season to focus on his medical career.
He has been in fine form in recent weeks but suffered the hamstring injury during last weekend’s United Rugby Championship defeat to Munster.
Amos is one of several first team regulars to sustain a significant injury at Musgrave Park or in training this week.
Rory Thornton came off with a shoulder injury, which is undergoing further investigation and specialist opinion.
Jarrod Evans suffered a hand fracture, which will rule him out of action for four to six weeks.
Kristian Dacey (hand) and Garyn Smith (calf) are also likely to miss the remainder of the season after sustaining injuries in training.
The quintet join the likes of Willis Halaholo, Josh Adams. Tomos Williams and club captain Josh Turnbull on the sidelines.
Unavailable for selection:
Six weeks plus
Hallam Amos
Theo Bevaqua
Will Davies-King
Rhys Gill
Willis Halaholo
Garyn Smith
Tomos Williams
Fewer than six weeks
Josh Adams
Scott Andrews
Kristian Dacey
Efan Daniel
Jarrod Evans
Rory Thornton
Josh Turnbull