Awadallah invited Castro's attorney, Craig Weintraub, to submit evidence to him before the meeting to support an argument against the death penalty in the upcoming discussions.
Castro's attorneys have previously hinted that he might plead guilty if talk of capital punishment was taken off the table.
Awadallah said prosecutors would be going back to the county grand jury to seek more charges against Castro, but he didn't know when that would happen.
At the end of the hearing, Castro, his bearded chin tucked to his chest for most of time, asked for permission to visit with the child he fathered with one of the women he is accused of kidnapping and raping. The judge denied the request.
"I just think that would be inappropriate," Russo said.
Castro has pleaded not guilty to a 329-count indictment alleging he kidnapped three women off the streets between 2002 and 2004 when they were 14, 16 and 20 years old and held them for a decade in his two-story home in a rough Cleveland neighborhood.
He fathered a 6-year-old daughter with one woman and is accused of starving and punching a second to cause her to miscarry. He was arrested May 6, shortly after one of the women broke through a door at the home and yelled to neighbors for help.
The trial is scheduled for Aug. 5, but Russo said it could be delayed. Another hearing is set for July 24.