Silva arrived in England in 2010 with a big reputation from his success with Valencia.
However, Hart recalls the little midfielder appearing tiny, slow and extremely one footed in early training sessions.
Silva has gone on to become one of City's greatest ever players.
The former City goalkeeper told the Kickback podcast: "The wizard came over, I had no idea who he was.
"£25 million, tiny, slow, only left footed and didn't even know his position.
"He seemed like a lovely guy, didn't really speak much English.
"He didn't take over straight away but his consistency and quality were through the roof.
"Just an all-round amazing player - there isn't one negative to him, other than he's small."