The offseason is training not just for the players, but for the coaches as well. This is something that Keith Butler talked about early on this offseason after the draft. Coaches are as much on a constant job interview as players are—even if the Pittsburgh Steelers have a better retention record with coaches than just about any other team.
And part of evaluating coaches—and for coaches to train—is to practice plays in multiple ways. Many of the offseason scrimmage practices are in scripted drills, where the play being run is known in advance, but Mike Tomlin talked about getting in work on play-calling in other scenarios during minicamp.