The England international has made several high-profile errors for the English Premier League champions this campaign.

Hart's latest mistake was in the lead up to Southampton's second goal in their shock 3-1 win over City on Saturday.

Hart also failed to clear in the build-up to Jason Puncheon's opener at St Mary's, a defeat that Mancini admitted has all but ended their title hopes, and the Italian has pointed the finger at his goalkeeper.

"It was a really bad mistake from Joe," Mancini told reporters.

"It was not good enough. It's not strange because he's done a few mistakes this year."

"Joe has made too many mistakes. He has not been good enough."

Hart was also criticised by Mancini after he slammed his team-mates following a 3-2 Champions League loss to Real Madrid in September.