Former Hurricanes lock Michael Fatialofa remains in hospital after suffering a neck injury playing in Worcester's 62-5 Gallagher Premiership defeat at Saracens yesterday.
The club provided a brief update this morning saying he was still in hospital.
"Warriors lock Michael Fatialofa has been retained in St Mary's Hospital in Paddington overnight," the statement said.
"On behalf of Michael we would like to thank all those who have passed on messages of support and concern."
Fatialofa had been on the pitch for just over a minute when he was hurt while taking the ball into contact.
Play was held up for almost 10 minutes as he received medical attention and, having been carried from the pitch on a stretcher, he was taken by ambulance to St Mary's hospital accompanied by the team doctor and a travelling reserve.
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"For me, a neck injury like that is a massive concern and I am worried about it, but I haven't had any report from the hospital," Worcester boss Alan Solomons said.
"It seemed like he dropped his head as he went into contact, but I haven't studied the footage. It seems like he's taken a blow to the neck.
"The medics have taken all precautions and have done everything possible. We've contacted his partner to let her know."
Saracens director of rugby Mark McCall added: "Our thoughts are with Michael Fatialofa. It didn't look great. His health is the most important thing."
Fatialofa, 27, made his New Zealand domestic rugby debut for Southland in 2011, before shifting to his home town of Auckland for the 2015 ITM Cup.
That move proved profitable for Fatialofa as, after one season with the province, he was selected to play for the Hurricanes in Super Rugby where he helped the side to their maiden title.
Fatialofa is currently signed with Worcester on a two-year contract from the 2018-19 season.