Wales, Ospreys back-row Dan Lydiate out of 2018 Six Nations

Dan Lydiate will miss the Six Nations and the rest of the season after undergoing surgery. David Rogers/Getty Images

Warren Gatland's 2018 Six Nations preparations have been dealt a blow with the news that Wales and Ospreys back-row Dan Lydiate has been ruled out of the tournament due to surgery on a bicep injury.

The back-row is an area where Wales already seem light with Sam Warburton missing the rest of the season with a neck injury and Taulupe Faletau a doubt for the Feb. 3 opener against Scotland after suffering a three medial knee ligament injury.

Now Lydiate can be added to that list after the flanker injured himself in Ospreys' New Year's Eve PRO14 victory over the Dragons.

Although early estimates suggested he may only miss the start of the Six Nations, the need for surgery has now blown that conservative estimation out of the water, with Lydiate now set to miss the entire season.

"After speaking to consultants and seeking specialist opinion, the decision has been taken in Dan's best interests to undergo surgery," Ospreys' medical performance manager Chris Towers said in a statement. "That process will take place this week, ruling him out of consideration for the rest of the current season."