Nigeria and Chelsea midfielder John Mikel Obi Saturday was ruled out of the World Cup due and will be replaced by Brown Ideye from French side Sochaux.
However, it remained unclear what kind of injury has sidelined the 23-year-old Mikel.
"We have dropped Mikel from the World Cup squad after he told the team he did not want to put his career at risk as his knee injury has yet to fully heal after a recent surgery," team official Emmanuel Attah said on a report on the Chelsea website.
The KickOffNigeria.com website quoted Nigerian team spokesman Idah Peterside as saying that "Mikel suffered a bruise to his ankle and a scan showed that he will not recover on time.
"The coach has now decided to call up Brown Ideye to replace him."
Mikel was sidelined with a meniscus injury since April but was set to play in Nigeria's final tune-up match on Sunday against North Korea.
Mikel is yet another Chelsea player out of the World Cup. Germany captain Michael Ballack and Ghana midfielder Michael Essien are definitely sidelined and Ivory Coast captain Didier Drogba very doubtful after breaking his arm Friday.
Ideye was originally one of several players dropped by Lagerback when he announced his final 23-player squad.
Nigeria, who arrived in the host country of South Africa earlier in the week, play Argentina, Greece and South Korea in group B at the World Cup.