Former Wales under-20 international Ifan Phillips sustained "life-changing injuries" after he was involved in a serious road accident involving two motorbikes.
The Ospreys confirmed on Wednesday their rugby prospect was "in a stable condition" at Morriston Hospital in Swansea after being treated for his unspecified injuries.
"Ifan is in a stable condition and he is uppermost in the thoughts of all of us at the Ospreys," the region said in a statement.
"On behalf of his team-mates, coaches, staff, all Ospreys supporters and the rugby community, we want to extend our full support to Ifan, his family and his friends.
"The family are overwhelmed and very grateful for the support they have received in the last few days. The Ospreys request Ifan and his family are given privacy at this difficult time and we will be making no further comment."
Ospreys head coach Toby Booth addressed the media on Wednesday and appeared to suggest Phillips will be forced to retire: "To have a career cut short through injury is very upsetting.
"He was very committed. It’s a very disappointing day."
Booth went on to acknowledge the difficulties caused by the accident "won’t finish tomorrow or the next day. They’ll be continuous for evermore."
"Obviously it’s terrible. Tragic. It’s very upsetting for all, especially himself and his family.
"Our deepest… words fail me a little bit, to be fair.
"Basically, we need to be there for Ifan in whatever capacity, in the short, medium and long term. We’ll do anything we can to support him through the next transition in his life."
The incident happened near Landore Social Club in Swansea, and South Wales Police have since released a statement appealing for witnesses to come forward.
The son of former Neath and Wales hooker Kevin made his debut for the Ospreys in 2017 and signed a contract extension with the club earlier this year.
It's understood Sunday's crash involved a green Triumph Street Scrambler and a Kawasaki, but South Wales Police are still seeking information in relation to the incident.
"Officers are appealing for witnesses following a serious road traffic collision that occurred at around 1.38pm on Sunday, 5 December on the B4603, Morfa Road, Landore, Swansea, opposite Landore Social Club," a statement read.
"The collision involved two motorcycles, a green Triumph Street Scrambler and a Kawasaki. One rider was taken to hospital, where he remains and is being treated for life-changing injuries.
"The road was closed for a number of hours whilst investigations continued and we thank anyone affected during this time for their patience.
"We would like to speak to anyone who witnessed the collision or has dash-cam footage, anyone who stopped to provide assistance, or anyone who saw the motorcycles prior to the collision."
Phillips' father played for Wales on 20 occasions and was captain on two occasions, though the current Ospreys talent is yet to win a cap for his nation's senior side.
News of Sunday's crash led to a swell of support and tributes on social media, from rival clubs as well as fans and supporters.
Cardiff Rugby responded in solidarity with their fellow Welsh region and tweeted: "Thoughts are with Ifan, his family and everyone at the Ospreys at this difficult time. If we can help in any way, you know where we are."
The Newport-based Dragons also messaged their condolences: "The thoughts of us all @dragonsrugby and with Ifan, his friends and family at this difficult time. Take care, stay strong we will support you in any way we can #rugbyfamily."
