Reports say that Wisdom, who joined the Championship club in 2017, was visiting relatives in Toxteth, Liverpool, when the incident took place.
“Andre Wisdom has been the victim of an unprovoked assault and robbery,” said a statement from Derby.
“He sustained injuries which resulted in him being admitted to hospital, where he is in a stable condition.
“Merseyside Police are investigating and the club will focus its efforts on supporting Andre and his family.”
Merseyside Police did not immediately respond to CNN Sport’s request for comment.
According to the Liverpool Echo newspaper, a Merseyside Police spokeswoman said “officers received reports that a 27-year-old man was walking to his car at around 4.30 am when he was assaulted by four men wearing masks and armed with knives.”