The Aquile are finally able to start investing this summer, as Joaquin Correa is on his way to Inter for €31m including bonuses.
Toma Basic already had his medical this morning following the move from Girondins de Bordeaux and the next target is a left-sided attacking winger.
Much like Basic, Kostic has been their first choice for months and rejected all other proposals so he could wait for the funds to be freed up.
His asking price is circa €35m, but with the sale of Correa, that becomes more feasible.
According to Sportitalia transfer expert Alfredo Pedullà, negotiations continue for the 28-year-old Serbia international.
Lazio are also discussing Zaccagni with Hellas Verona, but he would only be Plan B in case Kostic didn’t work out.
Kostic is much better suited to new coach Maurizio Sarri’s 4-3-3 formation.