I'd heard comments elsewhere that Rondo had put in a lot of endurance and footwork this off season intending to go back to doing more ball-pressure as well.
Considering that apparently Stevens himself was one of Rondo's main workout partners all summer, that may be representative of what Stevens intends to do defensively: Full court press.
He'll always be able to have two very good ball-pressure defenders on the court with Rondo, Bradley and Smart so this is something they could keep up all game.
It's tricky and risky if you don't have the right personnel, but if you have guys like Bradley who can 'stick' in front of his man like we've seen him do in the past, it really makes the rest of your defense better because they only have to defend a shorter shot clock.