During the third week of the preseason, it usually comes time for starters to be kept in the game for about three quarters. That's not always the case though with veteran-heavy teams. It's debatable whether we can call the Bengals a veteran-heavy team.
Marvin Lewis said Wednesday he'll be limiting his starters to a play count, not a quarter count. Lewis did say if the starters haven't played much going into halftime, they might play during the third quarter.
With seven of Cincinnati's projected 11 defensive starters having five+ years of experience, don't expect to see most of those guys for more than a half.
As for the offense, Andy Dalton will probably only see a half of work as well, but only because of his offensive line.
The Bengals will start rookie center Russell Bodine, and they'll likely pull Andrew Whitworth (nine NFL years) and Andre Smith (six) after a half of play; Dalton will go out with them. In the first two preseason games, once the Bengals backup line started playing, it's not gone well for whoever's been quarterbacking at that point.