London - Wales flank Dan Lydiate added to head coach Warren
Gatland's backrow problems on Tuesday after being ruled out for the rest of the
season with a bicep injury that will also see him miss the upcoming Six
The 30-year-old is to go under the knife after injuring his
bicep in Ospreys' PRO14 22-9 win over the Dragons on December 31, his club side
Lydiate, who has 62 caps but started just one of Wales'
Tests in 2017, joins fellow flanker Sam Warburton in missing the tournament.
"After speaking to consultants and seeking specialist
opinion, the decision has been taken in Dan's best interests to undergo
surgery," said Ospreys medical performance manager Chris Towers.
"That process will take place this week, ruling him out
of consideration for the rest of the current season."
Aside from Lydiate and Warburton's absences, Gatland also
has concerns over No 8 Taulupe Faletau, who is recovering from knee trouble and
won't be back until late February or early March.
Ross Moriarty, another back row forward, is also sidelined
The Six Nations gets underway on February 3.