Jack Clifford has been called up into England's training squad

Jack Clifford will join up with England's training camp in Oxford after Billy Vunipola was ruled out for four months following knee surgery.

Vunipola needed to be helped from the pitch during Saturday's 41-13 victory over Sale and scans confirmed he damaged cartilage in his right knee. He underwent surgery on Sunday morning and is expected to be sidelined for 16 weeks.

That rules Vunipola out of England's autumn internationals against Argentina, Australia and Samoa, which are all being shown live on Sky Sports.

The Premiership encounter was Vunipola's second match of his comeback from shoulder surgery which ruled the No 8 out of the British and Irish Lions tour to New Zealand and he also damaged the same knee against Argentina last November which sidelined the 24-year-old to a three-month absence.

Billy Vunipola was injured during Saracens' win over Sale on Saturday

Clifford's call-up comes after the Harlequins player had fallen out of favour within the England coaching set-up but has been offered a chance to re-integrate into the squad with the aim of building upon his previous 10 caps which have all come under Jones' tenure.

"This camp in Oxford is a really positive opportunity for the group to come back together and sharpen our focus and preparation ahead of our first match against Argentina," Jones said.

The former Australia and Japan head coach was watching in the stands as Clifford impressed in Harlequins' narrow 31-28 defeat by Leicester at the Twickenham Stoop.

Clifford becomes the fourth member of the Harlequins side that will join up with the 33-man England party, on Sunday, alongside Chris Robshaw, Mike Brown and Marcus Smith despite further injury concerns to the trio in the fixture.

Robshaw, the former England captain, will need to observe return to play protocols after being knocked out while Brown has an ankle problem which forced the full back to hobble through the closing stages after Harlequins had used up all their replacements.

"Chris Robshaw was an immediate removal from the pitch. He's fine and was up and about in the changing room, so there are no issues there," director of rugby John Kingston said. "Marcus was precautionary because he was tight around the calf area and the last thing I wanted was for him to carry on and pull a muscle when we have enough players unavailable.

"Mike Brown's ankle is sore, that actually happened last week. He became a dad in the middle of the week and he was always a question mark because of the ankle injury he got at Wasps. He scrubbed up to play and he took another knock on it - he was in quite a bit of misery. He managed to stay on to make sure we weren't short of players."

Dylan Hartley will miss a second successive match for Northampton

England captain Dylan Hartley, Harlequins' Joe Marler and Anthony Watson are already in the treatment room .

Hartley will miss a second successive match on Sunday against London Irish because of a hand problem while Watson is sidelined by a knee injury and Marler is being treated for a rib ailment.