London - England hope Maro Itoje will return for the end of their Six Nations campaign after he suffered a knee injury in his side's dramatic opening victory against Ireland.
Itoje will miss the matches against France and Wales but if his rehabilitation progresses well, the British and Irish Lions lock could be back for the last two rounds against Italy and Scotland.
Offsetting the news of his absence is the return to fitness of flanker Brad Shields, centre Ben Te'o and wing Joe Cokanasiga, who missed the stunning start to the championship in Dublin through injury.
"Maro had the scan and saw a specialist yesterday (Monday). It's ligament damage to his knee," said forwards coach Steve Borthwick.
"We anticipate him being able to play at the latter part of the tournament. Hopefully he'll heal fast and we'll have him back ASAP."
Itoje's Saracens team-mate Nick Isiekwe has been called into England's 35-man training squad ahead of Sunday's match against France at Twickenham.
Courtney Lawes, who was a second-half replacement against Ireland, and Joe Launchbury are competing to fill the vacancy in the second row alongside George Kruis.
"Maro's a fantastic player and a great personality around the squad," said Borthwick. "Clearly it's significant that he's out, but we have a lot of brilliant players in his position."
Itoje sustained the injury to his right knee in the second half of England's 32-20 win at the Aviva Stadium in Dublin when being cleared out of a ruck by Ireland flanker Peter O'Mahony.
He was also ruled out for five weeks after suffering a chipped patella to the same knee in the build-up to the autumn series, but played throughout England's four November internationals until the nature of the injury was discovered.