http://profootballtalk.nbcsports.com...reseason-game/

Matt Barrows of the Sacramento Bee reports that the Ravens and 49ers are planning to join up for practice and a scrimmage ahead of their August 7 preseason opener. Those practices would give both teams a chance to see their players against outside competition in a controlled setting, something that several teams do to change up their practice schedule in the summer.
Have they ever done a scrimmage before? I can't remember it happening before.