Bonucci had been a key figure for the Turin-based side in recent years, with Juve winning the last six Serie A titles in a row and Del Piero now expects his former side to hit back with a big signing of their own.
Italian international Bonucci left the club amid reports of a breakdown in relations between him and manager Max Allegri, with several sources claiming that the pair clashed during a Serie A game against Palermo last season and again in the dressing room at half-time in the Champions League final.
In an interview with Italian publication 'La Gazzetta dello Sport', Del Piero said: "It's a transfer that surprised me. We need to see what really happened to come to this conclusion."
"Juve has some very precise rules. In my 19 years there I watched behaviour by some players who were sanctioned with heavy fines."
"Evidently in this case we came to a situation that could no longer be recomposed."
From the outside looking it, it looks like Juve have had a mixed summer so far, losing Bonucci and Dani Alves and with rumours that Alex Sandro could also be set to leave the club, though Allegri has managed to bring in Douglas Costa from German giants Bayern Munich and goalkeeper Wojciech Szczesny from Arsenal. Del Piero is now expecting a major incoming, "Now I expect a very important shot by Juve," he said. "The purchase of a player who has not yet been talked about."
Who could it be? Let us know your guesses in the comments.