Ferreira has been released from Chelsea this month.
Carvalho told chelseafc.com: "He always did what the coach asked him, he doesn't want a problem with anyone, he only wants to have good relations with people.
"Of course, he chose to stay for a long time and in the last few years he didn't play so much but was always there to help and do a good job. I don't know if he will continue playing or not, he loves his family life in London, so he may decide to finish and stay in the area. I wish him good luck with whatever he chooses."