The 25-year-old Slovakia international has been linked with a move away from Naples throughout the summer.
"Hamsik is excited to play for Napoli and be a talisman of the group," Juraj Venglos told Radio Crc.
"For several years, Marek has been here and he is happy because he has gained a lot of experience.
"This year, Napoli are stronger. The club have signed reinforcements since the departure of [Ezequiel] Lavezzi and [Walter] Gargano. They will fight for the Scudetto this year."
Hamsik joined Napoli from Brescia in 2007.