England prop Andrew Sheridan is almost certain to miss the entire RBS 6 Nations, according to one of the UK's leading orthopaedic surgeons.
Sheridan was ruled out for four months by his club Sale last Monday, after it was revealed he required a full reconstruction of his left shoulder.
The 29-year-old Lions front row dislocated his shoulder during a collapsed scrum in Sale's Heineken Cup victory over Cardiff Blues on October 16.
Simon Moyes, who works at the Wellington Hospital, believes expectations that he will require just four months to recover are optimistic - and believes a minimum six months is more realistic.
"To determine the extent of the injury I would expect he had a scan followed by a surgical repair with either open or arthroscopic surgery," said Moyes.
"Patients (n these cases) are normally in a sling for six weeks and then undertake an extensive physiotherapy/rehabilitation programme.
"I would therefore expect Andrew Sheridan to be out of action for at least six months from the time of surgery."
Sheridan's name sits on an ever-lengthening injury list that is forcing England manager Martin Johnson to name a revised Elite Player Squad this afternoon.
Leicester prop Julian White became the latest absentee for the fixtures against Australia, Argentina and New Zealand when he tore his hamstring against London Irish on Saturday.
White joins fellow front-row forwards Sheridan, Lee Mears (knee) and Phil Vickery (neck) in missing the entire autumn series that starts against the Wallabies on November 7.
With England's outlook at prop hitting crisis point, 35-year-old Bath veteran Duncan Bell will earn a recall this afternoon after winning the last of his two caps in 2005.
Harlequins number eight Nick Easter, another key component of Johnson's autumn plans, left Sixways on crutches after suffering a calf muscle injury during Quins' 26-22 victory over Worcester.
In total, six guaranteed starters - and one of their replacements in White - have been ruled out of the entire series. Flanker Tom Rees, centre Riki Flutey and full-back Delon Armitage are also absent.
Johnson will also require updates on players such as Leicester scrum-half Harry Ellis and Wasps lock Simon Shaw, with neither Lion likely to be available for the Australia clash.