In this situation, Amir Johnson (15) is supposed to help out on Maggete to insure he does not get any easy jump shot. As you can see in the picture, Johnson is doing the right thing. Drummond is diving to the basket though, which means some sort of weakside help needs to come.
Here's what the play looked like in real time:
As you can see, its still the preseason and players are still figuring out their defensive rotations. I have full faith in Dwayne Casey, who improved the Raps defense exponentially last year, to fix small things like this. On the Detroit side, this play shows unexpected instincts/recognition from both Bynum and Drummond, which only bodes well for the future.