Marsh fears failure to secure successive titles will spell the end for the Italian.
He told talkSPORT: “I would not sack Mancini. I think he is a terrific manager.
"I think he has got good qualities. He is a terrific football man and he's actually the current manager of the champions. I personally wouldn’t make that change.
“But I have a feeling City are going to. I have a feeling that Man City will sack Roberto Mancini, even if they win the cup.”