Newcastle Falcons and England star Jonny Wilkinson will miss his side's match against Spanish side VRAC in the second leg of the Parker Pen Challenge Cup with a suspected stress fracture of the neck.
The injury will keep him sidelined for three weeks.
The injury was diagnosed after the England World Cup match-winner complained of pain in his shoulder.
It is likely this injury was sustained during the World Cup semi-final against France and not his recent car accident.
Wilkinson will miss Newcastle's game against Valladolid on Sunday and is doubtful for England's game against the New Zealand Barbarians next weekend.
After undergoing a precautionary x-ray on Thursday, Wilkinson will undergo a further CT scan on Saturday morning.
"The x-ray revealed an area of concern and further investigations were warranted," said a Newcastle statement.
"Obviously, the club will do nothing to put any player at risk from an injury standpoint, and we feel this is the best course of action to take," it added.