Several reports, including the Guardian's, claimed that the mother of the 21-year-old was abducted by unknown gunmen while driving along Okpulu Umuobo area in the city of Aba, Anambra State.
The report further stated that the kidnappers initially demanded a ransom of $40,000 but later raised the amount after being aware that Samuel is a professional footballer.
Though the player and the local police are yet to issue a statement regarding the incident, the family is said to be negotiating with the suspected kidnappers for her safe release.
This is not the first kidnapping case involving the families of Nigerian players as captain John Obi Mikel's father was kidnapped during the 2018 Fifa World Cup in Russia but was later released after a gun duel between the police and the kidnappers.
Meanwhile, Kalu was in action for 72 minutes in Bordeaux's 1-0 loss to Nantes on Sunday.
The 21-year-old joined the Girondins from Gent last August and has scored four goals in 29 games across all competitions in his debut season for the Ligue 1 side.