The 20-year-old is set to switch for a reported fee of €7.8 million (£6.61m) and is expected to sign a five-year deal.
The midfielder is co-owned by UK-based investment fund Doyen Sports and Lazio president Claudio Lotito previously expressed his frustration that talks were held up by the investment firm.
But Santos president Luis Alvaro Ribeiro says the English fund never stood in the way of the negotiation and there are only a few minor details now to complete.
He told Lancenet: "There are only few bureaucracy details to be defined.
"Santos had to define a few limits for the payments and closed only when it seemed right.
"The English fund is a partner of us and never stood in the way if the negotiation."