Former Sydney Roosters and Penrith prop Mose Masoe has undergone spinal surgery.
Masoe was taken to hospital, after hurting his neck during the opening minutes of Hull Kingston Rovers' 18-6 defeat in a pre-season trial match at Wakefield on Sunday.
His UK club says the 30-year-old Samoan international's injury is serious.
Masoe was given oxygen on the pitch, before being carried off on a stretcher and rushed to hospital in Leeds. He was operated on later that evening.
"Following the injury to Mose Masoe during yesterday's friendly with Wakefield Trinity, the club can confirm Mose has suffered a serious spinal injury and was operated on overnight at Leeds General Hospital," the club said.
"The club will provide further updates as soon as possible. "
Masoe played in the NRL for the Roosters and Panthers, before moving to St Helens in 2014 and is in his second full season with Hull KR.
He helped the Rovers gain promotion from the Championship in 2017.