Saracens prop Mako Vunipola has been ruled out of England's tour of New Zealand.
Vunipola, 23, dislocated his knee in Saracens' 23-6 Heineken Cup final defeat to Toulon in Cardiff last weekend and has had to undergo surgery.
The injury also means he will miss the Aviva Premiership final against Northampton.
A statement on the Sarries website said: "Mako Vunipola, the Saracens and England prop, has undergone surgery to repair a dislocation of the patella in his right knee, suffered during the Heineken Cup final last weekend. He will return to full fitness later this year."
England coach Stuart Lancaster has taken one set of tourists out to New Zealand already, and Vunipola was due to fly out with the second wave, made up of Saracens and Northampton players.
His absence deepens England's problems in the front row, with a host of props ruled out.
Harlequins' Joe Marler is another to be a concern for Lancaster - he is suffering a hip complaint.
England called up Bath's Nathan Catt as late cover for Marler in the initial group of tourists that flew out to New Zealand on Tuesday.
Wasps' three-cap loosehead Matt Mullan will now start England's first Test against the All Blacks in Auckland on June 7 unless Marler makes a rapid recovery.
One piece of good news for Lancaster was that Northampton hooker Dylan Hartley was fit enough to be named on the bench for the Premiership final.
The 28-year-old has not played for two months with shoulder trouble, but his return suggests he will be ready to fly out to New Zealand on Monday.
Saints prop Alex Corbisiero will not tour this summer having only just recovered from long-term knee trouble, and Leicester hooker Tom Youngs has been handed compassionate leave while his wife receives treatment for an illness.
England will take on the mighty All Blacks in the first Test with as many as 15 players unavailable.
Watch the first Test between New Zealand and England live on Sky Sports 1, with coverage from 8am on 7 June.