Nunez scored in the Champions League quarter-final first leg loss to Liverpool, and speaking before the second leg on Wednesday, Verissimo said of his potential departure: "It's the law of the market.
"Obviously players like Darwin, and the best players, the idea would be to keep them all, but we are in a competitive market, in which clubs need capital for their daily management, realising that he is having a very big evolution, he has an innate quality, he is building his way according to what he does individually and as a team.
"At the end of the season, if he has to go, we have to accept it, but it's the law of Realizing that in Portugal, things are the same.
"We have to face this from a perspective of hiring, valuing, enhancing, and then there are stronger markets and because of that there are players that we cannot keep. Benfica is no exception to that."