Ogbonna is expected to be targeted by a number of Italian and European outfits at the end of the season.
"I have a 'morale' agreement with Angelo," Toro President Urbano Cairo told Affari Italiani in an interview.
"A year ago he signed a contract with us when he had little over 12 months left on his previous deal.
"The economical conditions of the new agreement were important, but not extraordinary in respect to what a Real Madrid, a City or anyone else could offer.
"Therefore there is an understanding that I won't clip his wings if there are clubs who make offers for him.
"I certainly won't be the man who sends him away and I don't want to sell him at all costs. It all depends on his desire to stay.
"If we get to June and he wants to stay for another year or even longer then that will be great. Then, if he gets an offer of a lifetime, then we'll sit down and think about it."