There was a time when the Raiders and Cowboys would scrimmage against each other. That was back when the Raiders were still in Los Angeles and the Raiders held training camp in Oxnard. The two teams are discussing the possibility of sparking up those days once again, according to sources.
Since the Raiders moved back to Oakland in 1995 they have held training camp in Napa while the Cowboys have held their training camp in Oxnard. The Cowboys used to scrimmage with the Chargers but haven't done so since 2012 and Jerry Jones is very much in favor of the idea. He had also reached out to the Dolphins but they declined.
Usually the Raiders and Cowboys meet in the preseason but don't this year, making the joint practices a bit more possible.
Geographically, the only team whose training camp location is closer is the 49ers. The Raiders have had joint practices with the 49ers in the past but not since the preseason violence that caused the two teams to cease their annual preseason match-up for safety reasons. The two teams will play each other in the regular season this year.
The joint practices would occur in Oxnard between August 10-14. The Cowboys open the preseason right up the road in San Diego August 7 and the Raiders return from their first preseason game on August 8 with their preseason home opener on August 15 against the Lions.