He's just a puppy right? If he is then I wouldn't worry about it. When Earle was a puppy his ears were all over the place--up, down, half and half! It changed frequently. As he matured, his ears stayed up like a husky's are supposed to.

If he's an adult than his ear probably hurts. Bandit has one floppy ear right now. He has a cut inside his ear that likely hurts a bit so he's letting it flop while it heals.