The striker is on-loan with Galatasaray this season, with Napoli making him available for the summer market.
“Victor is always going to be a hotly-debated topic and not just on the transfer market,” Manna told Sky Italia.
“He is an appetising player for clubs, he has a clause and everyone knows this, we are working to find a solution as quickly as possible, so that we can avoid what happened last year.”
Manna also commented on the €75m January sale of Khvicha Kvaratskhelia to PSG.
He also said: “There are certainly regrets, as it is never easy to lose an important player mid-season.
“We talked about it a lot, but in my view the situation was also twisted. What it leaves me with is the intention to always be ready to deal with things we cannot control, but we are certain that we did the right thing there.”