A potato that is sprouting can be planted in order to grow more potatoes, according to GrowVeg.com. Potatoes that haven't started sprouting, however, are dormant and won't grow until dormancy has been broken.
Ideally, potatoes are grown from seed potatoes instead of sprouting potatoes found in the back of the pantry. It's best to let seed potatoes chit before planting them, according to Thompson and Morgan, which can be accomplished by letting them sit out in seed trays in full light until healthy sprouts form.
Chitted potatoes can be cut into egg-sized pieces, each with at least one sprout on it, before planting in order to produce more tubers.