Italy's formidable scrum will be less potent when they visit Lansdowne Road on Saturday week after Martin Castrogiovanni was ruled out for six weeks.
The Leicester prop fractured a rib during the first half of last weekend's defeat to England at the Stadio Olimpico. His club coach Richard Cockerill revealed the extent of his injury yesterday.
"The initial diagnosis is four to six weeks, and that's bad luck for Castro," he said. "He was really up for the England game and carried the ball a lot. But then he fell on the ball, got a bang in the ribs and he has cracked one."
Meanwhile, Chris Robshaw will lead England for the rest of the Six Nations.
"Chris has stepped into the role well and led a new team in two tough away fixtures," said stand-in coach Stuart Lancaster. "He is one of many leaders we could have chosen against Scotland and Italy but he has shown on and off the field the qualities required to captain a side."