The back-row sustained the injury in England's final autumn Test, against the Lions' last opponents, South Africa.
After further examination of the injury it has been revealed that there is no further damage to the shoulder other than the crack to the scapula.
A time-frame for Croft's injury has not yet been established. But he is certain to miss Leicester's busy festive period which includes the Aviva Premiership clash with London Irish and back-to-back Heineken Cup encounters with Perpignan.
"Tom will be treated by Leicester's medical team in consultation with the England medics," read a statement released by the RFU.
"The injury will be scanned again in three weeks time when a further announcement will be made."
The 25-year-old, who scored three tries in six games during the 2009 Lions tour of South Africa, is hoping to return to action before England's crunch Six Nations clash with Wales on February 4.