He was charged in May after a series of leaks exposed alleged corruption and internal conflicts at the Holy See.
Mr Gabriele's lawyer Carlo Fusco said his client had operated on his own in an "act of love" toward the Pope.
The so-called "Vatileaks" scandal saw an Italian investigative journalist publish hundreds of secret documents detailing fraud scandals, nepotism and cronyism within the Holy See.
Italian media reported in May that a stash of confidential documents had been found in the apartment Mr Gabriele shares with his wife and three children inside the Vatican.
"There are definitely no networks, no internal or external plots in which Paolo was involved. His motivations were all internal," AFP news agency reported Mr Fusco as saying.
"He wanted the Church to be more alive. He had an idea to help a situation."
The Vatican's judge, Piero Antonio Bonnet, has been instructed to examine the evidence of the case and to decide whether there is sufficient material to proceed to trial.
Vatican spokesman Federico Lombardi said a magistrate would decide whether to proceed by early August.