Napoli signed Brazilian goalkeeper Rafael from Santos on Friday in a deal believed to be worth $6.5 million.
The 23-year-old has spent his entire career with Santos, making 114 appearances since breaking into the senior team in 2010.
Napoli finished second in Serie A last season, meaning the team will take part in the Champions League this upcoming campaign, which was a major attraction.
"I always thought I would finish my career here at Santos but with the passage of time I realized that I wanted to play in Europe and in the Champions League," he told Football Italia.
Napoli manager Rafael Benitez has already signed a pair of wingers in PSV Eindhoven's Dries Mertens and Jose Callejon from Real Madrid.