Aaron Hernandez -- Judge's Order Gives Him Hope For a New Trial

Aaron Hernandez just got a glimmer of hope he could get a new trial -- a judge is compelling a tipster to come forward and testify about allegations one of the jurors in the murder case was biased.

TMZ Sports broke the story ... Hernandez's lawyers have been in contact with a woman who claims she recognized one of the jurors as someone familiar with Odin Lloyd's murder, and was angling to get on the jury panel.

But since the woman refused to reveal her identity in court ... Hernandez's legal team asked the court to force her to testify, and the judge just signed off.

According to docs, the anonymous woman will have to come into court and get questioned by prosecutors and the Hernandez legal team. The hearing will be closed to the public.