Zambia midfielder Clifford Mulenga has been sent home by coach Herve Renard for disciplinary reasons.
Mulenga, a fringe player based in South Africa, breached the team curfew when partying with three team-mates.
His colleagues apologised for their actions to team management but Mulenga is said to have shown no remorse.
"The young man has been disciplined for not accepting that what he did was wrong and out of order," said Zambian FA media director Eric Mwanza.
Meanwhile, a statement by the Zambian FA (Faz) said the body fully backed the decision taken by Chipolopolo coach Herve Renard.
"The decision was taken in the best interests of the team," a Faz statement said.
Mulenga has made only one brief appearance at the finals - coming on as a late substitute in their final group game against Equatorial Guinea.
It was after that game in the capital Malabo that he and the others failed to return to their hotel on time.
The identity of the other players involved has not been revealed but it is understood that Mulenga was the only one not to apologise.
Zambia topped Group A after two wins and a draw, and play Sudan in the quarter-finals in Bata on Saturday.
The squad, minus Mulenga, trained as normal on Tuesday evening after returning to Bata earlier in the day following Sunday's victory over the co-hosts in Malabo.
Additional reporting by Farayi Mungazi.