Mako Vunipola will miss England's Guinness Six Nations match with Wales on Saturday because of a medical issue, forwards coach Matt Proudfoot has said.
The Saracens prop was set to return to the fold after being included in an extended 34-man training squad on Monday.
But Proudfoot said: "Mako is not with us now. He has got a medical issue so he won't be available for the weekend. It is just something medical, so he is out for the weekend."
Vunipola had originally been expected to miss the clash with the Grand Slam champions after recently travelling to Tonga for unspecified personal reasons.
Quizzed on whether the 29-year-old would play any further part in the 2020 Six Nations, Proudfoot added: "We will take it week by week."
It means Joe Marler and Ellis Genge will be loosehead options at Twickenham for England head coach Eddie Jones this weekend.
"We were excited to have him back, he is a great presence and a very experienced player, but we have great depth in our looseheads and they have been playing well," Proudfoot said.
"We will give the guys a go who were there. Mako is a world-class player, but the guys have been doing a great job."
