A temporary 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 giants as he looks to resume his development.
According to reports, the player will join the Portuguese club on loan for two seasons, but it is unclear at the moment if they have an option to buy him at the end of that period.
Meanwhile, Barcelona have 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 their official website read.
Tello's path to the Barca first team was further blocked in recent weeks by the arrival of forward Luis Suarez from Liverpool.