If they were personally religious (spiritual) rather than socially/dogmatically religious, then it could work out. As an atheist, I'm not against spiritual beliefs, but their core values must align with mine - that is the important bit here. Obviously, communication about these things would determine where we align, and help determine if we could sustain a relationship, but it's certainly a possibility.

Note: I include a love of nature, humanism, etc. under the 'spiritual' label, as well as traditionally religiously spiritual.