Earls returns after missing the last six weeks with medial ligament damage to his left knee, an injury sustained in the Heineken Cup game against Edinburgh in January.
Young hooker Scannell trained after recovering from a hyper-extension of his right elbow in training last month.
Paddy Butler (neck), Ivan Dineen (ankle) and Luke O'Dea (ligament sprain) all started for Munster 'A' in their match against Connacht Eagles last Friday afternoon after recovering from recent knocks.
New signing Quentin MacDonald played an hour in that game and trained with the majority of the Munster squad for the first time today.
Longer-term absentees Niall Ronan, Mike Sherry, Cathal Sheridan and David O'Callaghan remain out for the foreseeable future and are continuing with their rehabilitation programmes.
Click here for more details on Munster's upcoming home fixtures.