England fullback Mike Brown will sit out training this week after bad concussion

One of England's most dangerous players remains a doubt for his team's upcoming clash with Ireland

Stuart Lancaster has shown his hand ahead of the crucial Six Nations match against Joe Schmidt's men on March 1. The England coach is not releasing any of the 15 players that started last weekend's win over Italy for Premiership duty. Lancaster has retained those players at the English training headquarters of Pennyhill Park for more sessions this week. Mike Brown, who was heavily concussed after 12 minutes of the Italy game, stays with the squad but will not train all week as part of the graduated Return to Play protocols. Interestingly, Billy Twelvetrees, who replaced Brown, and Exeter Chiefs fullback Jack Nowell will also train with the squad. It would seem Lancaster is preparing for the eventuality of Brown not being declared game-ready for the Dublin encounter. Nowell could come straight in at fullback or the coach could go with the backline that did damage to Italy in the opening hour of their match at Twickenham. That would mean Jonathan Joseph starting left wing, Jonny May fullback and Twelvetrees in the centre. Lancaster says, 'Mike is in in the early days of the graduated return to play protocol and will not be training this week. Geoff Parling, Tom Wood and Courtney Lawes will be released back to their clubs for further assessment and treatment with a view to them resuming training with us next week.'