Liam Williams has ruled himself out of any part of the 2024 Six Nations after his move to JapanDan Biggar and Liam Williams have been withdrawn from the Wales side to face South Africa in Saturday’s final World Cup warm-up game.Sam Costelow replaces fly-half Biggar who has a back spasm, while full-back Williams has a tight hamstring with Cai Evans handed his first cap.Tom Rogers has been named as a replacement.Head coach Warren Gatland will name his 33-man World Cup squad on Monday, 21 August.Wales stressed the injuries were purely precautionary and Biggar and Williams were not World Cup doubts.”They are not serious at all,” said Gatland.”Both of them (Liam and Biggar), if we pushed them hard, could play on Saturday, but the decision was made there is no point taking a risk at this stage. “I see it as a positive, really. It’s dealing with things that are going to been thrown at you. It’s using a bit of adversity as a positive.”Hooker Dewi Lake is in contention to be fit for the World Cup opener against Fiji in Bordeaux on 10 September with back row Taine Plumtree, hooker Ryan Elias and lock Dafydd Jenkins also targeting that game.Number eight Taulupe Faletau (calf) and fly-half Gareth Anscombe (thumb) are the only two players from the 48-man squad who have not been able to play in any of the three warm-up games. Lake was forced off the field after captaining the side in the 19-17 defeat against England at Twickenham last weekend.Dragons hooker Bradley Roberts has been called in to train with Wales to provide cover amid the injuries to Lake and Eias, who suffered a hamstring injury in the 20-9 opening World Cup warm-up win against England in Cardiff in early August.Roberts’ fellow Dragons hooker Elliot Dee will start against South Africa with Sam Parry on the replacements bench.Gatland admitted it was a balancing act about how many players he could select with fitness issues.”We have in the past gone to World Cups carrying players with niggles that are going to take two or three weeks to come right,” said Gatland.”That may be the case but it’s just depending on what sort of risk do you potentially take.”There are maybe one or two we can take with niggles, that’s probably the number you talk about.”The important thing is when you can get back to training. If you look at the draw, you’ve got to go fully loaded for the first game, then looking at Portugal with a six-day turnaround there’ll be changes.”Then you’ve got eight days to Australia where you’ll be a strong side again and then a 13-day turnaround where hopefully everyone gets an opportunity to recover from any bangs and bruises before you play Georgia.”There’s less pressure in this tournament than there has been in the past where you’ve had four-day turnarounds when that’s had quite a significant impact on the squad.”That’s a discussion we’ll have in terms of risk and how many we can carry.”Wales team to face South Africa: C Evans; Cuthbert, Grady, J Williams, Dyer; Costelow, Hardy; Domachowski, Dee, Assiratti, Carter, Rowlands, Lydiate, Morgan (capt), Wainwright.Replacements: Parry, N Smith, H Thomas, Teddy Williams, Basham, Tomos Williams, Llewellyn, Rogers.