Silva, 21, scored four goals in 12 games while on loan with Uniao de Leiria last season and it is hoped his latest switch will be even more beneficial.
Having hit 14 goals in his first full season of senior football with hometown club CD Aves, Silva attracted interest from a host of top clubs.
Everton boss David Moyes won the race to secure his services, with Silva signing a three-year deal at Goodison Park last summer.
But he was part of their reserve squad last season before being sent on loan to Portuguese top-flight side Uniao de Leiria, for whom he scored a brace in a 3-3 draw away to Benfica.
Silva had played both games during Everton's recent tour of Russia and now has the chance of regular first-team football back home.