City's expensively-assembled squad crashed out of the Champions League at the group stage, finishing last in Group D without a victory against Real Madrid, Borussia Dortmund or Ajax.
Their performances led to much criticism of Mancini with his team also failing to fully fire in defence of their Barclays Premier League title so far, sitting six points adrift of leaders United.
But Silva said Mancini was not the man to blame.
"We're responsible for what has happened," he was quoted saying by several newspapers. "The way we played in the Champions League - we all have to take the blame for that.
"It didn't start well in the Champions League and it became an uphill task. But you can't just blame the manager."
Silva credited Mancini with bringing major improvements to City during his time in charge.
"All I would say is that since I joined City up to now we have made progress with Roberto," he said. "All there has been is progress."
City's injury-time loss to United in last weekend's Manchester derby was their first defeat of the season in the league, but with the gap growing at the top Silva admitted there was much work to do to retain their crown.
Pulling it off, the 26-year-old said, would rank among his greatest achievements in the game to date.
"It would be right up there with all the other big competitions that I've won," he said. "Winning the Premier League is seen as a big thing. It would be a great achievement to retain it. I've been lucky I've won a lot of medals but I'd still like to win more."
Silva has recently been joined at City by two more Spaniards, with the club bringing in chief executive Ferran Soriano and director of football Txiki Begiristain.
The pair previously held the same positions at Barcelona, and Silva hopes City will one day be held in the same regard as the Catalan club.
"They were part of a club which won every title there was to win in both Spain and in Europe. They were part of a very successful era at Barcelona," he said.
"Hopefully that's what they are bringing here and we can do something similar. We hope one day we'll be able to be a club that is talked about like Barcelona.
"It's hard to say we're close to that because, although we won the Premier League, we went out of the Champions League, but it's a question of working at it and trying to make more of an impact in Europe."