Wales' George North faces an anxious wait to see if he will be fit for the British and Irish Lions tour of South Africa after suffering a leg injury on Saturday.
North, turning out for the Ospreys against the Cardiff Blues, appeared to get stuck in the turf during the second half of the opening Pro14 Rainbow Cup match.
The 29-year-old three-quarter looked to be struggling with a knee injury as he was helped off the field at the Liberty Stadium.
Assisted by two medics, he limped off down the tunnel and was eventually put on crutches.
North will now undergo scans to reveal the extent of the damage.
"You always worry when people get injured when no one is near them," Ospreys coach Toby Booth told reporters.
"That doesn't normally bode well for anybody so that makes it sound like it's structural."
Booth added: "I know you are going to ask me how bad it is but I don't know.
"The next 48 hours are crucial in relation to assessment and management. We've got a very good medical team with a lot of experience."
North, whose tally of 105 caps includes three Test for the Lions during their victorious 2013 tour of Australia, played a key role in Wales winning this season's Six Nations Championship
Although best known as a winger, he was deployed at centre by Test coach Wayne Pivac in the Six Nations.
North, who was also on the 2017 Lions tour of New Zealand before a hamstring tear ruled him out of a drawn Test series against the All Blacks, was back out wide in a match the Ospreys won 36-14.
This versatility was seen as a bonus when it came to gaining a place in Lions coach Warren Gatland's squad for a July-August trip that includes three Tests against world champions Springboks.
The New Zealander, a former Wales coach, is due to name his tour party on May 6.