Care has been in impressive form so far this season and had been talked about as a possible Lion but he will now have to wait until next week at the earliest to continue his push for selection in Ian McGeechan's South African touring party.
The 22-year-old former Leeds player will be replaced in the England squad by Leicester's Harry Ellis who moves from the Saxons set up straight into the senior starting XV.
"We all feel for Danny and wish him a speedy recovery," said England team manager and former Lions skipper Martin Johnson.
"Harry is an experienced international and I'm sure he will do a good job for us on Saturday."
Ellis is now in line to win his 23rd international cap having just served a six-week suspension for a dangerous tackle on Perpignan's Dan Carter in a Heineken Cup encounter in mid-December.
With Ellis chosen to start the match against the Azzuri, Northampton's Ben Foden remains on the bench for what could be his first outing in England colours.
Paul Hodgson of London Irish replaces Ellis in the Saxons line up for their clash with Ireland A at Donnybrook tomorrow night, with Wasps youngster Joe Simpson stepping up to join the Saxons replacements.