England prop Mako Vunipola needs surgery on his hamstring and has been ruled out for at least three months, according to England's Rugby Football Union.
The 28-year-old was injured in Saracens' 20-10 Champions Cup final win over Leinster on Saturday.
He will miss the remainder of his club's Premiership campaign but should recover in time for the World Cup in Japan in September.
GET WELL SOON, MAKO š@Saracens and England prop @Mako_Vunipola ruled out for three months: https://t.co/Bq2PjYzfTM pic.twitter.com/Vr5m8VYQwC
ā England Rugby (@EnglandRugby) May 17, 2019
"Vunipola's hamstring injury requires surgery and will take a minimum of three months to recover," the RFU said via a statement.
Vunipola's club coach Mark McCall was confident the tighthead would be back in time for rugby's showpiece tournament.
"Mako won't be out of the World Cup, but he'll be out for a while. It's quite a significant injury," he said.
Vunipola, 28, missed a large chunk of the Six Nations with an ankle injury and then suffered another problem to the same joint that resulted in an aborted comeback.
The European final against Leinster in Newcastle was only his second match since England's rout of France in mid-February.
He will miss the home Premiership play-off at Allianz Park on May 25 and the final a week later, if defending champions Saracens manage to reach Twickenham.
England play Wales on August 11 and 17, Ireland on August 24 and then face Italy in a final pre-World Cup warm-up game on September 6.
They kick off their World Cup Pool C campaign against Tonga on September 22.
