West Ham United midfielder Felipe Anderson is expected to join Porto on a season-long loan deal on Tuesday.
Although the transfer window closed for English clubs signing players from abroad on Monday, the window in Portugal is open until 25 October.
Brazil international Anderson joined the Hammers from Lazio for £36m in 2018 - a club record fee at the time.
But the 27-year-old is yet to start a Premier League game this season and is one of the club's highest earners.
Anderson was described by West Ham as "one of the most exciting talents in Europe" when he arrived on a four-year deal, and he has 12 goals and 12 assists in 72 appearances for the club.