Since his emphatic defeat to David Haye in a title unification match last year, Maccarinelli overcame Mathew Ellis in two rounds before slumping to a surprise ninth-round knockout against Ola Afolabi in March.
His latest comeback was short-lived against Lebedev - a third-round stoppage.
"All I can say is Enzo doesn't become a bad fighter overnight," said Calzaghe, who retired as the undefeated world super-middleweight and light-heavyweight champion last February.
"He will have to go away, take time with his family and decide for himself what he wants to do."
Meanwhile, Calzaghe has also warned fellow Welshman Nathan Cleverly to build slowly towards a world title fight.
Cleverly, 22, is targeting a world title tilt after stopping Danny McIntosh to retain his Commonwealth light-heavyweight title and take the vacant British title at London's York Hall on Saturday.
It has left Cleverly hungry for more big-fight success and some pundits such as Barry McGuigan and Duke McKenzie tipping him to emulate Calzaghe's success.
But Calzaghe said: "He has to keep his feet on the ground. It's still early days. You can't get carried away.
"While they are talking about world titles, he shouldn't be in a rush.
"He hasn't fought anyone who can hit back yet. He knows he's gaining experience with every fight.
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