The deal has become an official piece of news after the club released a statement on their website regarding Callejon.
It is believed that the 26 year-old has already passed a medical which he undertook earlier in the week and will be in Naples on a four year contract.
The former Spanish under-21 international who joins for a fee of around 9.5 million euros made 30 appearances in the Liga last season, scoring 3 goals and making a further 6 assists.