Michy Batshuayi was poised to complete a move to Fenerbahce on Friday after finding himself frozen out at Chelsea.
The Belgium striker had a successful loan spell with Besiktas last season and was linked with Nottingham Forest this week, before that City Ground switch failed to come to fruition.
It has since emerged he is heading back to Turkey's Super Lig to join Fenerbahce, who announced his impending arrival.
Fenerbahce – fierce rivals of Besiktas – said in a statement: "Our club has reached an agreement with his club for the transfer of Michy Batshuayi to our team.
"The footballer is coming to Istanbul to conduct negotiations, undergo a medical checkup and continue the process."
Batshuayi will be seeking regular club football to ensure he is in optimum shape in time for the World Cup in Qatar in November.
With a year remaining on his Chelsea contract, he looked to have no first-team future at Stamford Bridge, particularly after the Premier League club brought in Pierre-Emerick Aubameyang from Barcelona on Thursday.
Batshuayi has been a Chelsea player since 2016 but has started just five Premier League games for the Blues, while making 45 appearances off the bench in the competition.
He scored eight goals in the league for Chelsea but has not featured since the 2019-20 season, being farmed out on loan to Borussia Dortmund, Valencia, Crystal Palace and latterly Besiktas.
With his contract at Chelsea due to expire next June, a fresh started awaited the 28-year-old former Marseille player as he headed back to Turkey to put the finishing touches to his latest move.