An artificial disc device for replacing a damaged nucleus is disclosed. In one form, the device may be inserted in components such that the device may be assembled within and retained by the natural annulus therein. In another form, the device may be inserted into the natural annulus in a collapsed or compressed state or arrangement and then be expanded within and retained by the annulus therein. In a further form, the device may be provided with a releasable connection so that the device may be connected in an insertion configuration and may be released in an operable configuration. Insertion tools and methods are also disclosed.