It would be unwise to overreact to the performance of a team during the preseason. A team could readily go 0-4 in the preseason and go on to win the Super Bowl. Exhibition performances are largely not accurate barometers of team quality.
Still, the Pittsburgh Steelers have to have some level of disappointment over how their first-team defensive unit—or how much of it was out there for the game—performed against an admittedly explosive Atlanta Falcons offense that never the less was without some of its most important contributors, including a couple of Pro Bowl skill position players at running back and wide receiver.