If I am buying a DAC, does my CD player matter?

If I buy a DAC, and my CD Player is just a transport...doesn't that mean the CDP is nothing more than a machine that spins a disc and pass info to the DAC? Wouldn't the DAC's sound overrides the CDP's so therefore it wouldn't really matter what kind of CDP I have?

I am asking because I read alot about the synergy between transports and DACS and don't really understand how it all affects sound quality.