A loan deal is expected to be confirmed in the coming days after Barcelona gave the 22-year-old permission to go to Portugal to negotiate a transfer.
The 22-year-old winger has failed to cement a place in the Barca first team, coming off the bench in most of his 22 league appearances last season, and will join the Portuguese giant as he looks to resume his development.
WORLD CUP: Beautiful people | Germany homecoming
According to reports, the player will join the Portuguese club on loan for two seasons, but it is unclear at the moment if the club has an option to buy him at the end of that period.
Meanwhile, Barcelona has confirmed that a move is close, revealing that the player traveled to Portugal on Tuesday.
"The forward had permission from the club to travel to Porto to negotiate with the Portuguese team," a statement on the team's official website read.
Tello's path to the Barca first team got even harder in recent weeks by the arrival of forward Luis Suarez from Liverpool.