Wales full-back Liam Williams could face a lengthy lay-off after being injured at the World Cup.

Wales head coach Warren Gatland says he thinks the Saracens player could be out for three months with an ankle problem.

He was hurt during a Wales training session in Tokyo last week, and has had surgery in the UK.

Williams was ruled out of the tournament and replaced at full-back by Leigh Halfpenny for the semi-final defeat against South Africa.

A three-month absence would sideline him from Saracens' Heineken Champions Cup pool games and a number of Premiership fixtures.

Wales, meanwhile, kick off their 2020 Six Nations campaign under new head coach Wayne Pivac against Italy in Cardiff on February 1.

"I think he had surgery yesterday," Gatland said. "I think it will be three months. That surgery takes about that long.

"If we had made the final, he would still be here with us. In fairness to Saracens, they had agreed that. But if we weren't, they wanted to get him back for surgery as quickly as possible."

Wales conclude their World Cup campaign by tackling New Zealand in the bronze medal match on Friday.