Nigeria rocked by injuries to attackers Moses and Uche
Injuries to Victor Moses and Kalu Uche have left Nigeria short of attackers for June's World Cup qualifiers and the Confederations Cup in Brazil.
The pair's withdrawal from the squad deepens problems for coach Stephen Keshi, who was already without Nations Cup joint-top scorer Emmanuel Emenike.
Keshi said: "It's unfortunate that they informed us when we have already finalised our provisional squad.
"It is now too late to start calling up replacement players."
English Premier League side Chelsea informed Nigeria that Moses requires treatment for a recurring injury, while Kalu Uche said he has played with an injury throughout the season in Turkey and, on the advice of his doctor, will be using the off-season to undergo treatment.
"I've been playing with some injuries but doctors are insisting I rest it now, so it means I will miss these games for Nigeria," Uche told BBC Sport.
"It's always a great honour to represent my country but I have been ordered to respect my body and take a rest.
"I wish the team all the best and I hope to return a stronger and better player soon."
The Super Eagles will keenly feel the absence of Moses and Uche, who scored 19 goals for Kasimpasa to end the season as the second top scorer in Turkey.
But Keshi added that he "remains confident" Nigeria have enough quality to get good results in the World Cup games against Kenya and Namibia as well as in the Confederations Cup.
Nigeria are level on points with Malawi at the top of their World Cup Group F.
After three matches both sides have five points, with only the top team in each group going through to the next round of qualifying for a place at the tournament in Brazil next year.