Milan Vice-President Adriano Galliani admits he wouldn't know how to react if Leonardo were to replace Rafa Benitez at Inter.
Leonardo spent over a decade at Milan first as a player, then as a director and finally as a Coach.
He left by mutual consent in the summer after one season in charge, citing differences of opinion with Silvio Berlusconi.
"I don't know what my reaction would be," Galliani told Sky Italia. "He certainly has a very important history with Milan.
"I remember perfectly when I went to sign Leonardo in Paris in 1997. He had a 13-year career at Milan.
"Last year things didn't go badly because we could have done better than third place without the many injuries.
"There was a misunderstanding between Leonardo and Berlusconi and I am sorry about this."
Looking back at Milan's start to the season, Galliani said: "We don't play as well as during the time of the great Arrigo Sacchi, but the players are very determined, very strong and have a lot of desire.
"I hope that in 2011, we win something after three years. Milan are in the running for three trophies. We are looking to win one of these and maybe even more than one, who knows.
"Ibra is perhaps doing better than the rosiest expectations but he has always been a great warrior. He frightened me when I saw him play for other teams.
"When we played the derbies with Ibra on the other side, his strength, character and determination put me on edge."