Everton have been linked with a move for two Turkish Super League players this summer.
Nani is understood to have an €8 million release clause included in his contract. The Portuguese international won four league titles and the Champions League at United but left the club after falling out with current head coach Louis van Gaal.
The 29-year-old joined Fenerbahce for £4.25m on a three-year deal over the summer transfer window and despite being well settled in Istanbul his recent interview suggests that he would consider a return to England.
Boyko has been tipped to leave Besiktas despite joining from Dnipro Dnipropetrovsk for €3.3 million in January. The former Dinamo Kiev keeper has failed to break into the first team and has made just two appearances for the Black Eagles.
Everton have endured a difficult season and will be looking to improve their squad over the summer transfer window. The Toffees are in 11th place with 41 points in 34 games.