Brad Barritt and Luther Burrell are England's latest injury concerns, handing Stuart Lancaster a serious shortage at centre.
Forwards Tom Croft and Christian Day have been called up to England's RBS 6 Nations training squad as injury cover.
Scottish Rugby Union chief executive Mark Dodson has defended Vern Cotter's decision to include Hugh Blake in his squad.
Wales centre Scott Williams admits he was surprised by the international retirement of prop Adam Jones.
Ireland chiefs remain hopeful Eoin Reddan will beat his medial knee ligament strain in time to face Italy in the Six Nations.
Former England scrum-half Kyran Bracken says Nick Easter is capable of switching to second row amid an injury crisis.
Saracens forward Will Fraser will miss the rest of the season after a decision was taken to operate on his injured back.
New Zealand wing Frank Halai will join Wasps from Auckland's Blues next season.
London Irish have continued their recruitment drive with the signing of scrum-half Brendan McKibbin from the NSW Waratahs.
World Cup-winning head coach Gary Street has left his post in charge of the England Women's side by mutual consent.