No, it need not. But maintaining consistency with naturalism is a significant constraint for a theist.
Even with an open mind toward an expanded or liberal view of naturalism, using the word at all means accepting the truth that our world is a systematically evolving network of related events which share the same underlying fundamental character. This means that there is no room for intermittent supernatural intervention from a transcendent God. It also implies there is no dualism involving souls or spirits which interact with our world. This means no miracles, no intercession to answer prayers, no resurrection, for example.
Doesn’t this mean no God or religion at all?
If you follow the debates on evolution and other hot buttons in the conflict between science and religion you might think so. The most brilliant and eloquent defenders of scientific naturalism, such as Richard Dawkins and Daniel Dennett, are indeed atheists. Those who feel threatened by science are of course those with the most traditional or fundamentalist religious views.
But there is a huge area of religious belief which is not threatened by accepting the truth of naturalism as I’ve defined it. Systems traditionally known as deism, pantheism, and panentheism come to mind. Certainly there are modern Christian and Jewish theological perspectives which are compatible with the findings of science. There are two roles potentially ascribed to God. First, as a transcendent creator: especially for those who think the questions “why something rather than nothing?” or “why this kind of world?” are real and important questions which are not answerable by present or future science. The second role is an immanent presence infused into nature itself: the wonder and reverence we feel in experiencing the world is identified with God’s being in the world.
My point here is just that the polarization which seems to characterize the cultural conflict between science and religion is unnecessary given the large area of concord which can exist between naturalism and forms of theism. I know this perspective is not new news, but it certainly doesn’t get much “air time.”