Ansbro has returned to London Irish for treatment while the rest of Andy Robinson's squad step up their preparations for the Murrayfield encounter with the reigning 6 Nations Champions.
The Cambridge University graduate will be reassessed by the Scotland medical staff after the England game and it is hoped he could recover in time for the trip to Wales the following weekend.
"Joe came into our camp in St Andrews last week affected by a back injury which will need a longer period of rehabilitation," said Scotland's lead physiotherapist Paul McGinley.
"This will be undertaken at his club and he will be reassessed following the England game."
Ansbro currently has nine international caps to his name and has scored two tries since making his debut in the stunning win over South Africa in November 2010.
He became the first black player to represent Scotland and was the favourite to wear the No13 in this season's 6 Nations.
While Ansbro's absence is a blow for the Scots, there was some good news with the confirmation that David Denton is fit to return to training.
The Edinburgh back row was a late withdrawal from his side's Heineken Cup clash with Ansbro's London Irish a week ago after suffering discomfort in his hamstring.
Denton, who won his first Scottish cap when he came on as a second-half replacement in the August Test against Ireland, has since been given the all clear to resume full training and will now look to press his claims for a starting spot following Kelly Brown's enforced absence.