The 20-year-old on Thursday signed a new and improved contract in which he committed to the club until June 2020 with a release clause that cannot be activated before June, reports Xinhua news agency.
"He is the best young player in Argentina and is worth at least 20 million euros," Racing President Victor Blanco said.
"There are half a dozen clubs that want him and he'll have the chance to choose which league he wants to play in when the moment arrives."
Last year Martinez's agent, Rolando Zarate, said Real Madrid and Atletico Madrid had expressed interest in signing the forward.
Martinez, an Argentina under-20 international, has scored four goals in six league matches for Racing so far this season.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
