WALES full-back Liam Williams could miss the NatWest 6 Nations with an abdominal problem.

The 26-year-old suffered a recurrence of the injury playing for Saracens in the 15-15 draw against Ospreys in the European Champions Cup.

Head coach Warren Gatland revealed that unless the problem does not respond to treatment Williams will need an operation.

"If he's not right unfortunately he might require surgery," said Gatland.

Wales also confirmed that fly-half Dan Biggar will miss the first three matches of the tournament with a shoulder injury.