The Exeter Chiefs back-row ruptured his anterior cruciate ligament against Worcester last weekend and will be unavailable for England’s autumn and Six Nations campaigns.
Simmonds was not included in Eddie Jones' training squad despite his excellent start to the season.
It is a significant blow for Exeter Chiefs who have won all 5 of their opening games.
“If the operation and rehab goes really well we’d like to hope we can maybe see him before the end of the season but it’s going to be touch and go,” the Chiefs’ director of rugby, Rob Baxter, said. “It’s hard to absorb because Simmo has been a key momentum gainer for us. Obviously he is upset. He was looking forward to having a big season.”
The only possible upside, Baxter reckons, is that Simmonds should be back fit and raring to go in mid-summer if England’s pack require any 11th-hour reinforcements. “The other guys are going to be playing and are more likely to be picking up injuries than Sam,” Baxter said. “Two or three of them might go down yet. He may well find that, if he manages to get a big month in with us before the end of the season, he could look like the guy who is absolutely flying.”
Baxter, who has lost another of his England squad forwards, Jonny Hill, for up to four months with a finger ligament injury, is also confident that Simmonds will ultimately come back stronger. “Yes he’s going to miss some big games now, but you’d hope those big games can get added on to the end of his career because he’s not taking the battering now.”