De Bruyne (34) has left Manchester City for title defender Napoli, while Modric (39) joined AC Milan from Real Madrid.
Locatelli insists that both midfielders will have a positive influence on the Serie A.
He said to Sky Italia: “De Bruyne and Modric are two champions, two legends of today's football. It is an honor to challenge them to face them.
“I played against them before, and there are so many things that I could learn from both, but the really nice is to compete with them.”
Lazio legend Paolo di Canio said last week about the veteran -Duo: “I don't want to be a torpedo hunter, but I have two analyzes. The first: I will enjoy their game, but I am sorry that no one has sought them in Europe. They have not taken even the third, fourth or fifth forces.
“We will see the creativity of the Croatian or the passes of the Belgian, with rhythms, timing and spaces that are easier for them. But the Italian football, from Ronaldo to Ribery, brings people to the dusk.
“Ik wil een term op een vriendelijke, niet-afgeleide manier gebruiken: de begraafplaats van nobele olifanten. Als kinderen zeggen ze dat ze ons voetbal hebben bekeken, maar ze zijn er nog steeds op 40 uur. Ze komen op prachtige plaatsen, maar naar een toernooi dat in hun herinneringen het WK 2006 is, met Cannavaro, een verdediger, en de Ballon D'Or D'Or D'Or D'Or D'Or D'Or D'Or.”