The lawyers say the Academy Award-winning actress could be called to the stand to testify in the April murder trial of William Balfour, the Chicago Sun-Times reported.
Hudson hasn't been identified as a witness but defense attorney Amy Thompson cited possible evidence -- a text message Hudson exchanged with her mother around the time of the mother's fatal shooting.
Hudson is best known for her Oscar-winning performance in the movie musical "Dreamgirls."
Balfour, 30, is the estranged husband of Hudson's sister, Julia.
Thompson's request came Tuesday as she and Cook County prosecutors argued over whether there was probable cause for Balfour's Oct. 24, 2008, arrest in the Chicago killings.
Detective say Julia Hudson let Balfour use a bathroom at her home in the city's Englewood neighborhood hours before her family members were killed there. Julia Hudson had told Balfour she was seeing another man and didn't want to speak to him but still let him in the home, Wentworth Area Detective Tim Nolan said Tuesday. Balfour was standing on the porch of the home when she left for work, Julia Hudson told detectives.
When she returned, her mother, Darnell Donerson, 57, and brother Jason Hudson, 29, were found shot to death, retired detective Allen Szudarski testified. Julia Hudson's son, Julian King, 7, was found fatally shot in Jason Hudson's stolen sport utility vehicle on the West Side three days later.