Darkseid would be stupid to confront Bannerless Hulk in physical combat. Like Scoob said, he'd have to finish Hulk off quickly. But come to think of it, there arent many ways to harm Hulk without the influence of Banner. But with his matter transmutation, he MIGHT be able to revert him back to Banner, but I doubt it. Not even Vision could do that by re-arranging his molecules.