A statement by the team’s Media Officer, Samm Audu, said Wilfred Ndidi, a central defender, is one of the several additions to the squad, which is drawn mostly from the Nigerian league.
“The squad has 18 home-based players, with three foreign-based players,’’ it said.
The statement listed the three foreign-based players as Belgium-based goalkeeper John Felegha, Michael Olaitan of Greek champions Olympiacos and Edafe Egbedi of Danish club AGF Aarhus.
It said 16 of the 21 players featured at the 2013 African Youth Championship (AYC) in Algeria, where Nigeria placed third to qualify for the World Cup.
The Flying Eagles are drawn in the first round group with Portugal, champions in 1989 and 1991; debutants Cuba and South Korea.
Nigeria, quarter-finals losers to France at the 2011 FIFA U-20 World Cup in Colombia, will face Portugal in their opening game on June 21.
The full squad: Goalkeepers — Samuel Okani (Enyimba), Jonah Usman (ABS FC) and John Felegha (Eupen, Belgium).
Defenders — Shehu Abdullahi (Kano Pillars), Moses Orkuma (Lobi Stars), Ikechukwu Okorie (Enyimba), Kingsley Madu (El-Kanemi), Chizoba Amaefule (Dolphins) and Wilfred Ndidi (Nath Boys).
Midfielders — Agboyi Ovbokha (Bayelsa United), Abduljaleel Ajagun (Dolphins), Christian Pyagbara (unattached), Uche Agbo (Enyimba) and Michael Olaitan (Olympiacos, Greece).
Forwards — Edafe Egbedi (AGF Aarhus, Denmark), Daddy Moses (Unattached), Chidi Osuchukwu (Dolphins), Umar Aminu (Wikki Tourists), Olanrewaju Kayode (unattached), Alhaji Gero (Enugu Rangers) and Samuel Eduok (Dolphins).