Ospreys and Wales centre Ashley Beck has been ruled out for two months after suffering significant ankle ligament damage.
Beck was a try-scorer in Wales defeat to Samoa last November, but will now miss the majority of the Six Nations.
"Ashley suffered a significant ligament injury to his ankle during the New Year's Eve fixture at Rodney Parade," said Ospreys head of physio.
"We've conducted investigations over the course of the last week to determine the full extent of the ligament damage and plan his rehabilitation effectively.
"Based on the advice received, we are currently treating this as a 6-8 week injury so would expect to see him back in action by the end of February."
Jamie Roberts, Jonathan Davies, Scott Williams and James Hook are all currently available.