If you’re making the meatballs from scratch, the cooking time can stay the same, but you’ll want to make sure they’re firm enough to hold up in the slow cooker. Use a binder like egg and breadcrumbs, and chill them before adding to the Crockpot. They won’t fall apart if they’re well-formed, but this method is definitely gentler with frozen meatballs. It’s doable, just not quite as carefree.