Jonny Wilkinson has little more than a 30 per cent chance of featuring in England's Six Nations game at Croke Park tomorrow after the most relentless injury jinx in sport struck again on the eve of the squad's departure for Dublin.

The World Cup-winning outhalf did not train yesterday and is having treatment on what is officially described as "a tight right hamstring". Brian Ashton, the head coach, is prepared to delay a decision until tomorrow morning, but Toby Flood is on standby to make his first full England start and Mike Catt has flown out as cover.

With doubts also about Jason Robinson, who is understood to have a 50-50 chance of recovering in time from a neck problem, the loss of the pair would put a significant dent in England's plans for their most serious examination since Ashton took charge.

Robinson and Wilkinson have scored all but five of England's 62 points in this season's championship, and supporters were daring to believe the 27-year-old Wilkinson's grim luck with injuries might be over. A combination of physical and mental fatigue kept him from playing for Newcastle at the weekend, but he ran without obvious discomfort in training on Wednesday morning and described his fitness as "good". Details of how he suffered his latest setback were not being divulged by the Rugby Football Union last night.

England cannot afford to field an injured Wilkinson unless they are prepared to risk losing him for another extended period. They may have little choice but to promote Flood and put the 35-year-old Catt on the bench, with Harlequins' David Strettle set for his debut if Robinson misses out. "There will be no decisions on Jason and Jonny for at least another 24 hours, when we will assess the situation again," said Ashton.

Flood (21), has won only four caps, all as a replacement, and has kicked only three points for his country, compared with Wilkinson's monumental haul of 859. And if Catt features it will be another remarkable twist in the career of a player who appeared in a victorious English team in Dublin during the amateur era.

Italy coach Pierre Berbizier has made three changes to his starting line-up for the match against Scotland at Murrayfield tomorrow. Flanker Mauro Bergamasco and centre Andrea Masi reclaim their places after recovering from injuries that kept them out of the 20-7 defeat to England.

Josh Sole's failure to recover from the elbow injury he picked up at Twickenham gives Calvisano flanker Alessandro Zanni (23), his first Six Nations start.