Cardiff's Williams recovering from neck surgery
Leicester player Owen Williams (left) passes the ball to Blaine Scully during the European Cup rugby union match at the Marcel Michelin stadium in Clermont-Ferrand, central France on April 5, 2014 - by Thierry Zoccolan
The Cardiff Blues and Wales centre was hurt while taking part in the inaugural World Club 10s competition just over a week ago.
The 22-year-old underwent surgery in Singapore, where he was joined by his parents and brother.
A Blues statement issued Monday said: "Owen was safely transferred by air ambulance from Singapore over the weekend and is currently being assessed and monitored by specialists at University Hospital Wales.
"Cardiff Blues and the Williams family would like to take this opportunity to pay tribute to all the staff and specialists at Tan Tock Seng Hospital in Singapore for their care and support for Owen following his injury.
"Owen and his family would also like to thank well-wishers for the overwhelming messages of support they continue to receive on a daily basis from around the rugby world.
"Cardiff Blues will continue to share any appropriate updates when available, and again requests that the privacy of Owen Williams and his family is respected at this time."
Last week the Blues said Williams had suffered "a significant injury to his cervical vertebrae and spinal cord".
Williams was injured while playing for the Blues in a third place play-off game against Asia Pacific Dragons.
He has so far won four Wales caps, making his debut on last year's tour of Japan, while he scored a try in the 17-7 Millennium Stadium victory over Tonga in November.