The Biancocelesti are doing really well on all three fronts, but boss Vladimir Petkovic is aware his team are somewhat short of options in the centre of the park.
With Ederson and Brocchi struggling through injury and Onazi away on Africa Cup of Nations, the Bosnian coach is eager to sign another midfielder in January.
Il Corriere dello Sport understands the Biancocelesti have made Sao Paulo’s Casemiro their number one target.
Lazio president Claudio Lotito has already established initial contacts with the Brazilian giants, but he is not willing to match their €10 million valuation.
Having already signed Hernanes and Andre Dias from Sao Paulo, Lotito hopes the Brazilian club will settle for €6 million.
Casemiro, 20, has already made 91 league appearances for the club, and has scored 9 goals in the process.