Lazio president Claudio Lotito has praised Sergio Floccari's camp.
Floccari left Lazio last month for Sassuolo.
Lotito said: "I want to publicly thank Sergio Floccari and his agent for their decision to leave now [for Sassuolo] when he could have signed for free with any club from February 1.
"There are agents who earn millions taking players away from clubs on free transfers."