Further assessments are required to establish the extent of Webb's injury. Photo: Neil Munns/BackpagePix

LONDON – Wales scrumhalf Rhys Webb will miss the Six Nations Championship with a knee injury, the Welsh Rugby Union (WRU) said on Thursday.

“Rhys Webb has been released from the Wales National Squad due to a knee injury,” the WRU said in a statement.

“The injury will restrict Webb's involvement in the campaign and further assessments are required to establish the best course of action.”

The omission of the 29-year-old Webb was the latest injury setback for Wales ahead of their opening match against Scotland in Cardiff on Feb. 3.

Warren Gatland's team were already facing issues in their back line with experienced flyhalves Dan Biggar (shoulder) and Rhys Priestland (hamstring) ruled out of the opening Six Nations games.

Uncapped Cardiff scrumhalf Tomos Williams has been called into the squad.