Lobotka is expected to make the switch to the Stadio San Paolo for just under the €35m release clause.
“I will never announce a transfer unless it is official," Lobotka told Pravda as he prepared for a celebrity tennis gala.
“I can confirm that I have been in contact with Napoli for a long time, but we are still negotiating. Until it's all written and signed on paper, I won't say anything more.
“I would love to go to Napoli, as it's an excellent club with a great Coach, they play in a great league and are regularly in Europe.
“Celta Vigo told me very clearly that if they have an interesting offer, they have no problems letting me go, but it has to be a suitable proposal.
“It's difficult to say when a deal could be done, as transfers can be complex. I'd like to see it through and I think we'll know something by the end of June.
“Napoli aren't the only candidates, as there is an English club interested too, but they're further behind. I won't specify the club's name.
“A transfer to Napoli would be a big step forward for me, as they challenge for the title. They play beautiful football and I am attracted to their ambition."