Sprouts on a potato does not mean that the potato is bad.
Potatoes are not bad or unsafe to eat just because they have sprouted.
You can cut off the sprouts of the potato and still eat the rest of the potato.
When a potato goes bad the potato will get mushy and soft to the touch and usually the bad potato will start to leak fluid out of the potato.
If the potato does not smell bad or is firm to the touch then the potato is still good and safe to eat even if the potato has sprouted.
Just make sure to remove the potato sprouts before cooking the potatoes because there can sometimes be toxins underneath the sprouts.
But just because the potato has sprouted it does not mean the potato has gone bad.
I've used and cooked sprouted potatoes for years and never have gotten sick from any of those potatoes.