This can be a tuffie :) You should know the piece well enough to play it smoothly and steadily on your own, so that you are not totally dependant on the drummer for your timing. This is especially important in expressive music where you don't always play exactly on the beat. With Jazz, for instance, you typically play just ahead of the beat, while in Blues, you usually play just behind the beat.

If you wait to hear the drum before you play the note that falls on that beat, obviously you will be far too late. You have to get synchronised with each other so that your pick is approaching the string as his stick is descending toward the drum head.

It may take a while to get familiar with each other, but it does come with practice. If you take turns starting a tune, you get used to taking your cues from each other.