I'd be inclined to plant it either in a pot or in the ground in a patch of pure gritty sand, to encourage it to grow some new roots. Just in soil it might rot at this time of your year. I'd also dust it with a fungicide to be on the safe side.
A lot of paeonies grow from pieces of root, i.e. root cuttings so if there's a bit which could be detached, try that in a pot of damp sand, maybe with a rooting hormone.