Cardinal Edwin O'Brien

Cardinal Edwin O'Brien doesn't know what will come out of the Synod on the Family set for October, but the former archbishop of Baltimore believes it will be significant.

"Hold onto your seats," O'Brien told a gathering of seminarians and faculty at St. Mary's Seminary and University in Baltimore.

"I think Pope Francis wants to stir things up and allow people to raise questions.

I don't think we're going to see a change in doctrine, but we will see a change in tone, and we might see some disciplinary modifications."

Those modifications might include adjustments in annulment procedures, O'Brien said.