Jonny Wilkinson has emerged as England's latest fitness concern for their RBS 6 Nations showdown with Ireland at Croke Park on Saturday.
The fly-half superstar missed training on Thursday due to a combination of bumps, bruises and a tight right hamstring.
And England's concern is such that Wilkinson's fellow World Cup winner Mike Catt has been summoned to join the squad that will fly to Dublin.
Catt will be joined by uncapped Harlequins wing David Strettle, who will provide cover for neck injury victim Jason Robinson.
England head coach Brian Ashton says no decision on either Wilkinson or Robinson will be made for "at least another 24 hours."
The possible loss of both Wilkinson and Robinson would represent a double blow for Ashton following Twickenham victories over Scotland and Italy.
Wilkinson, two Tests into his comeback following repeated numerous injury problems, has scored 42 of England's championship points this season, while Robinson has scored three tries.
Ashton said: "There will be no decisions on Jason and Jonny for at least another 24 hours, when we will assess the situation again."
England though, say Robinson has made a good initial recovery from Wednesday's training blow at Bath University, and will receive on-going treatment.
Wilkinson and Robinson, joined their colleagues at Heathrow en route to Dublin, although England stress both Catt and Strettle have flown as "precautionary cover".
Wilkinson missed Newcastle's Premiership defeat at Bristol last Sunday due to what the Falcons termed "bumps, bruises and strains".
His Newcastle colleague Toby Flood stands by to replace him, while 35-year-old Catt finds himself back in the mix.
London Irish back Catt, capped 67 times, has not played for England since the second Test against Australia in Melbourne last summer. His last appearance against Ireland was in 2001, when England blew their Grand Slam hopes at Lansdowne Road.
Flood, 21, has not yet started a Test match, but the prospect of running out with England in front of an 83,000 Croke Park crowd is something he must now consider.
Wilkinson has played just twice for England since the 2003 World Cup final, but Ashton drafted him back into the side against Scotland three weeks ago, and he responded by equalling the individual Calcutta Cup record of 27 points.
While England fretted over the fitness of two key players, Ireland confirmed scrum-half Peter Stringer's recovery from a broken hand that means he reclaims his place in the starting XV.