Nigeria still hope they can persuade Sidney Sam to play for them despite his call-up to the Germany squad for two upcoming friendlies.
Sam was born by a German mother but his father comes from Nigeria so he could represent any of the countries.
Germany are set to try out the 24-year-old against Ecuador on 29 May and against the United States three days later.
But Nigeria are “optimistic” Sam has not shut the door on them.
The Nigeria Football Federation has been pursuing Sam since last November but has struggled to satisfy all the requirements for the Bayer Leverkusen midfielder to switch allegiance from the country of his birth.
“We are still working on Sidney Sam and we are aware that Germany have invited him for non-competitive games,” NFF spokesman Ademola Olajire told BBC Sport.
“Some officials have been mandated to handle this and they’ve intensified their efforts since last week.
“The Super Eagles are at present camping in Germany and our officials have been in touch with Sam to fast-track the process.
“We are optimistic he will play for Nigeria whether he turns out for Germany now or not.”
BBC Sport understands Sam is keen to try out his options without committing himself to either country at this stage – and Germany’s friendly matches give him the chance to do so.