According to Sportitalia, Lazio have increased their proposal for Santos striker Marcos Leonardo and included a percentage of the sell-on fee.
The asking price remains €15m, but the Biancocelesti hope they can lower that with the addition of a cut of any future sale.
Meanwhile, the fixed fee has been stepped up to circa €12m and a conference call is set for tonight to discuss the situation with the Brazilian club.
Marcos Leonardo only turned 20 in May and is a centre-forward who impressed at the Under-20 World Cup.
A product of the Santos youth academy, he scored nine goals and provided three assists in 25 competitive appearances for his club this season.
He had also been linked with Roma, Manchester United, Arsenal, Newcastle United and West Ham, but Lazio have been the most persistent.
Lazio are in need of a striker who can act as understudy to Ciro Immobile, as the captain’s injury problems often left them using Felipe Anderson as a False 9.