LONDON (AP) — Wales could be without Liam Williams for the entire Six Nations tournament because the fullback may require surgery for an abdominal injury.

It is the latest injury blow for the Welsh, who are also set to be without flyhalf Dan Biggar for the first three rounds of the tournament while he recovers from a shoulder injury.

Fellow No. 10 Rhys Priestland is currently out with a hamstring injury, and flankers Dan Lydiate and Sam Warburton will miss the whole tournament. No. 8 Taulupe Faletau is recovering from knee trouble and may not be available until the third round.

Williams' abdominal injury is a recurrence of a problem that previously kept him out for six weeks.

"Hopefully they can get him right but if he's not right, he might require surgery," Wales coach Warren Gatland said at a Six Nations launch event in London on Wednesday. "He potentially had the option of surgery before, and that was not taken up."

With Biggar and Priestland missing, Rhys Patchell and Gareth Anscombe look to be vying for the flyhalf berth for Wales' opening game, against Scotland on Feb. 3.

"The exciting thing is that we're going to pick a player who hasn't started in that position in the Six Nations," Gatland said. "Opposition teams know Dan Biggar pretty well, so we could potentially have a flyhalf that the opposition don't know a lot about."

Wales last won the Six Nations in 2013.

"People are writing us off, which is nice," Gatland said, "and I'm expecting us to do well."