EurosportThe move means Morris, who has not played since breaking both the tibia and fibula in his right leg late last season, can not return for at least another eight weeks.
Scans in May found a stress fracture in the fibula, which the Bulldogs said at the time would sideline Morris for at least another six weeks.
But he can now not return until at least round 21, if he plays at all this season.
Campbell's elevation puts him in line for a potential AFL debut against Brisbane on Saturday, in place of regular ruckman Will Minson.
Minson was suspended by the club on Tuesday over an unsavoury comment made to Port Adelaide's Danyle Pearce last weekend.
Morris, 29, said he would still aim to return to this season.
Having come off the rookie list to make his own AFL debut in 2005, the 151-gamer said he was pleased his injury at least gave another rookie a chance.
