The jurors spent nine hours deliberating on Tuesday and Wednesday.
Hernandez is charged with the June 2013 shooting death of Odin Lloyd, who was dating his fiancée's sister. Lloyd was shot six times in an industrial park less than a mile from Hernandez's home.
On Wednesday, jurors asked questions to clarify two weapon and ammunition possession charges Hernandez faces in addition to the murder charge.
Jurors must deliberate every day from 9 a.m. to 4:30 p.m., and may go later if they wish.