The 24-year-old damaged his left knee in Saints’ 21-19 defeat to Saracens in their Guinness Premiership semi-final clash at Franklin’s Gardens.

Leicester’s Geoge Chuter has been drafted in to replace Hartley after a scan revealed he will require an arthroscopy to treat the damaged cartilage.

The news will come as a blow to Martin Johnson as Hartley has grown in maturity since being handed the Northampton captaincy at the beginning of the season.

Brive front-rower Steve Thompson and his Bath counterpart Lee Mears are the ones most likely to take Hartley's place in the two upcoming Tests against Australia, with Chuter and Wasps' Rob Webber also among the touring party.

The RFU has also confirmed the withdrawal of three players from the England Saxons squad for the Churchill Cup.

Wasps flanker Tom Rees, who saw his season blighted by a shoulder injury, will stay at home to continue his rehabilitation, with Leeds' Kearnan Myall drafted in as his replacement.

Bath lock Stuart Hooper is replaced by Newcastle's James Hudson after suffering a toe injury in his club's semi-final defeat at Leicester on Sunday, while London Irish hooker David Paice has failed to recover from a quadricep injury in time to tour. A replacement for the Exiles man is to be announced at a later date.