The incident happened in Swansea on Sunday and Phillips was taken to Morriston Hospital, where Ospreys say he is in a stable condition.
Phillips, 25, is the son of former Wales hooker Kevin and has played 40 games for Ospreys and trained with Wayne Pivac’s Wales squad last summer.
An Ospreys statement was released below:
“The Ospreys can confirm hooker Ifan Phillips was involved in a serious road traffic accident in Swansea on Sunday afternoon and is now being treated at Morriston Hospital.
“Ifan is in a stable condition and he is uppermost in the thoughts of all of us at the Ospreys.
“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.”
South Wales Police has launched a public appeal following 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 South Wales Police statement said.
“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.”