Williams injured his back playing for the Ospreys and will continue his rehabiliation away from the Welsh camp.
A statement from the WRU reads: “Scott Williams has been released from Wales’ 2019 Guinness Six Nations squad to continue rehabilitation of his back injury at his Region (Ospreys). It is felt that his injury will preclude him from taking a competitive part in the competition.
“An update will be provided later today regarding players released back to their Regions for action this weekend.”
Wales coach Warren Gatland has warned his side that things could get “embarrassing” when they meet England in two weeks time if they put out an effort like they did against Italy.
While Wales equalled their longest test winning streak at 11 with a 26-15 triumph over the Azzurri on Saturday, they looked far from their best on the pitch.
Both sides scored a pair of tries but the boot of Dan Biggar proved the difference as the first five-eighth nailed four penalty goals.
England looked impressive last week when they beat Ireland 32-20 in Dublin, and Gatland knows his team must take things up a level if they are to defend their home ground against Eddie Jones’ men.
“There are lots of things we need to improve for England,” Gatland told ITV post-match.
“The lineout was a bit concerning, we didn’t have enough tempo. We kept having to step away and Italy closed down that space pretty quickly.
“If we play like that against England it could be embarrassing.”
Gatland also explained the reasoning behind the plethora of changes he made to the lineup before the Italy clash.
“I probably need to take some criticism myself in terms of making so many changes and perhaps not having that continuity,” he said.
“But the plan was double-edged with looking at the Six Nations and ahead to the World Cup.
“We came here and did a job, got a win and can start thinking about the next two weeks which could already potentially be a championship decider.”
Wales haven’t beaten England since the 2015 Rugby World Cup, and have been usurped from their World No. 3 spot by England after last weekend’s results.
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