Inspirational play-maker Nwankwo Kanu may miss Nigeria's next Group F game against Sweden after undertaking medical tests.
Kanu was elbowed in the ribs early on in the Super Eagles' 1-0 defeat
to Argentina, and had to be substituted shortly after half-time.
And coach Adegboye Onigbinde conceded that the Arsenal player may struggle to recover in time for the Sweden game, which takes place on Friday in Kobe.
"We hope he will be fit, but if not, we have some other boys who can take
his place up," Onigbinde said.
However, Onigbinde added that he was relieved that the tests had shown that Kanu had only received severe bruising.
"He was taken for medical check-ups, and we have discovered it is not anything very serious.
"It is just a tissue problem and we are fortunate we have about five days to the next match."
Nigeria were severely weakened after Kanu's injury, with the player making little contribution in either attack or defence.
Onigbinde revealed why he had not made a substitution earlier in the game.
"I was reluctant to pull him out because if you look at my team you will
discover we have few experienced players here," he explained.
"I believed that keeping him
in the game would keep spirits up."