During a period of the late 1980s-early 1990s, it used to happen with the Washington Redskins. Starting this summer – pending NFL approval – it will happen with the Buffalo Bills.
The Bills and Steelers have agreed to hold joint practice sessions on a home-and-home basis during the 2014 and 2015 training camp periods. The Steelers will host the Bills this summer, with Buffalo serving as the host in 2015.
This is a natural fit in many different ways. First, the geography works out nicely with the Bills being at St. John Fisher in Western New York and the Steelers training at Saint Vincent College in Latrobe. Also, since Bills General Manager Doug Whaley went to the Bills from the Steelers, where he had served in a variety of capacities in the player personnel department, he has an understanding of how each franchise conducts its training camp.
That should allow there to be a level of comfort in terms of the ability to reach agreement on many of the details of such an undertaking, because coaches like to be in control of their teams' schedule and especially so during the training camp period.
The dates and times of the team activities will depend on when the NFL releases the entire preseason schedule, and then the dates, times, and sites of the teams' respective preseason games will determine the logistics of the joint practice sessions.