Rugby World Cup 2015: Wales' Alun Wyn Jones could miss opener

Alun Wyn Jones was captain in Wales' 16-10 win against Ireland in place of Sam Warburton, who was rested

Wales second row Alun Wyn Jones could miss their opening World Cup match against Uruguay on 20 September because of a knee injury.

The British and Irish Lions player sustained the injury as he captained Saturday's 16-10 win against Ireland.

Wales head coach Warren Gatland has named five locks in his 31-man World Cup squad.

"Alun Wyn should only be out for a couple of weeks but you never know with medial [ligament] stuff," said Gatland.

Gatland expects prop Samson Lee to be fit to face Uruguay following an Achilles tendon injury, but full-back Liam Williams needs further assessment before he can return to action after undergoing foot surgery.

Wales' head coach has also suggested he could use players outside the 31-man squad for their final World Cup warm-up match against Italy on Saturday, 5 September.

"We've spoken briefly as coaches that the squad or the team we pick against Italy may include one or two players outside of that 31," he said.

"We need to keep players involved and interested, and also to keep other players fresh and injury-free."

After the announcement of that squad, Gatland had high praise for Ospreys captain Jones: "That engine room is so important for us. He was outstanding on the weekend.

"[Lock] Bradley Davies in his first game for five months gave us a lot as well so we have players who can do a job for us," Gatland added.

Jones is one of five specialist second-rowers in Wales' final World Cup squad, the Ospreys captain joined by Jake Ball, Luke Charteris, Bradley Davies and Dominic Day.

There is also a place for Jones' regional team-mate James King, usually a blindside flanker but with experience of playing as a lock.

"Even though we consider him a back-row forward, he does have the ability to go and cover that second row," said Gatland.

Wales' 31-man World Cup squad

Props: Tomas Francis (Exeter Chiefs), Paul James (Ospreys), Aaron Jarvis (Ospreys), Gethin Jenkins (Cardiff Blues), Samson Lee (Scarlets).

Hookers: Scott Baldwin (Ospreys), Ken Owens (Scarlets).

Locks: Jake Ball (Scarlets), Luke Charteris (Racing 92), Dominic Day (Bath), Bradley Davies (Wasps), Alun Wyn Jones (Ospreys).

Back-rows: Taulupe Faletau (Newport Gwent Dragons), James King (Ospreys), Dan Lydiate (Ospreys), Justin Tipuric (Ospreys), Sam Warburton (Cardiff Blues, capt).

Scrum-halves: Gareth Davies (Scarlets), Rhys Webb (Ospreys), Lloyd Williams (Cardiff Blues).

Fly-halves: Dan Biggar (Ospreys), Matthew Morgan (Bristol), Rhys Priestland (Bath).

Centres: Cory Allen (Cardiff Blues), Jamie Roberts (Harlequins), Scott Williams (Scarlets).

Wings: Hallam Amos (Newport Gwent Dragons), Alex Cuthbert (Cardiff Blues), George North (Northampton Saints).

Full-backs: Leigh Halfpenny (Toulon), Liam Williams (Scarlets).