The 24-year-old has impressed since joining from Santos in 2014.
Meanwhile, in the Premier League Crystal Palace have signed England winger Andros Townsend from Newcastle for £13m.
He'd only been on Tyneside since January, but has moved on after their relegation from the Premier League.
Dwight Gayle has gone in the opposite direction in a £10m deal.
Manchester City have signed striker Nolito from Celta Vigo.
