Suarez is currently serving an eight-game ban after being found guilty of racially abusing Manchester United defender Patrice Evra and will not face City in their Carling Cup semi-final first leg on Wednesday.
Mancini said: "I think that sometimes a situation like this can happen on the pitch. It is important to apologise for what he did.
"Sometimes on the pitch you can do something that you don't want to do. You are nervous. You don't think on the pitch. I don't think Suarez is a racist. He made a mistake? Probably, yes.
"'Everyone can do a mistake sometimes. It is impossible that we are always perfect. It is important to say, 'I am sorry, I made a mistake, I apologise for this and I accept the charge'."