Centre Mike Tindall, prop Andrew Sheridan, wing David Strettle, plus flankers Lewis Moody and Tom Rees had already been ruled out.
And Vickery could now join them after injuring his right calf during training in Bath on Thursday morning.
England say it is too early at this stage to make an announcement on his fitness for Sunday, but uncapped Bristol prop Jason Hobson has been drafted into the squad and will travel to Rome on Friday, as will Vickery.
Given England's chronic run of luck with injuries, it will be a major surprise if Vickery regains full fitness in time.
If he is forced to withdraw, then Bath's Matt Stevens would undoubtedly be promoted off the bench with Hobson joining the replacements.
Vickery said: "It happened during training this morning in some contact drills.
"I will know a bit more later. I don't want to sit here saying I've got a 50-50 chance because I haven't got a clue.
"We have got a travel day tomorrow, and I will be travelling to Rome."
The possible loss of Vickery would be another hammer blow to England head coach Brian Ashton.
Ashton has had enough on his plate reviving England following their shock 26-19 defeat against Wales at Twickenham last Saturday.
But the injury scourge will just not go away, and Ashton could now even find himself having to appoint a new skipper for the weekend.
Fly-half Jonny Wilkinson, who has come under fire for his own performance against Wales, would probably be favourite to replace Vickery as leader, but another strong candidate would be Bath lock Steve Borthwick.