"I wanted to be sure that he still had the same old fire," Conte said on Italian television. "He's a warrior. He told me he was available and that's good enough for me."
Pirlo is currently sidelined until October with a hip injury, which means he will miss Italy's friendly with the Netherlands in Bari on Friday and the Euro 2016 qualifier against Norway in Oslo the following Tuesday.
Conte coached Pirlo at Juventus for the last three seasons, in which they won the Serie A title every year, before taking over from Cesare Prandelli as national coach.
Although he spoke about Pirlo, Conte refused to be drawn over Mario Balotelli, the new Liverpool striker who he omitted from the squad.