England lock Courtney Lawes' British and Irish Lions hopes could be in doubt after he was ruled out for 12 weeks.
The 32-year-old Northampton forward will have an operation on a pectoral muscle injury he sustained while training with England last week.
With the Premiership season due to end in mid-June, Lawes may not play again before the Lions squad to tackle South Africa is selected by Warren Gatland.
Lawes has played just four times since having ankle surgery in October.
He started twice for Northampton in December and featured in England's opening two Six Nations matches - starting against Italy - before his latest injury.
He is the second potential English Lions player to see his chances hampered by injury.
Exeter wing Jack Nowell - who, like Lawes, featured in the final two Tests of the 2017 tour of New Zealand - has also been ruled out until the tail end of this season.
England have called up Lawes' uncapped Northampton team-mate David Ribbans, 25, to their squad for the rest of the Six Nations campaign.
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