Bonucci, 31, caused a stir in the summer of 2017 when he swapped Turin for Milan after seven trophy-laden seasons with the Old Lady.
But the centre-back failed to find the imperious form that had marked him out as one of the world's elite defenders in his new home, amid constant instability on and off the pitch for the club.
And on his first day back at the Rossoneri, Leonardo admitted that his namesake was close to making an exit.
“I’ve met some people, not just those from Juventus,” the 1994 World Cup winner, who has represented Milan as player and coach, told reporters in Thursday's press conference.
“We’re bound to FFP, so it won’t be a crazy market. It’ll be moderate and wise. The desire [to talk to Juve] started with Leonardo Bonucci, so if we can, we’ll make it happen. We have no objection to it.
While affirming that Bonucci was seeking a way out, Leonardo added that he could yet stay for another term at Milan, who have recently fallen into the hands of US hedge fund Elliott Management.
“It all started from an idea, a very sensible and quiet one. It’s from here that all the talk started," he stated.
“It’s very normal for a player to have a wish. A player doesn’t just ask to leave, there’s also the project and objectives to consider.
“He arrived last year as a symbol for change. In great harmony, we’ll try to see what will happen. It’s not definite that he’ll leave.”