Mason was injured in the first period of a loss to Boston on Saturday. General manager Ron Hextall says it's a separate injury from the one kept him out of practice last week and required an MRI exam.
Mason is 8-12-6 with a 2.46 goals-against average and .920 save percentage. Emery is 7-7-1 with a 3.21 GAA. Zepp allowed three goals and won his only career NHL start at Winnipeg on Dec. 21.