Nigeria will have to bid for a second Olympic football gold medal without Olympique Marseille full back Taye Taiwo after his French club refused to release him.
A Court of Arbitration for Sport (CAS) ruling last week allowed the return of several Under-23 players to their clubs.
Nigeria's Olympic football coach Samson Siasia said the absence of the 23-year-old Taiwo would not affect the team's chances.
"I'm very disappointed. But one individual cannot make or break a team. It takes a team to win the medal and in spite of everything training is going well," he said.