Middlesbrough chief executive Keith Lamb is reported to have flown to Istanbul in an attempt to convince Fenerbahce winger Tuncay Sanli to move to the Riverside Stadium.
Birmingham City, Olympiakos, Hertha Berlin and Villarreal are also believed to be interested in signing Tuncay.
Last week Tuncay said: "All players aspire to play in big clubs such as Chelsea or Manchester as well as other big clubs in Spain or Italy.
"I am of the opinion that it is very tough for a player to be part of the starting line-up in those clubs and I would rather play for a team that I know will give me the chance to start."