Not all ligament tears are the same. If it's torn clean (Grade III), then yeah, he's done for the year. But given how he walked to the locker room without a limp and without grimacing in pain, it looks on its face to likely be a mild to moderate Grade II sprain. If that's the case, he could miss anywhere from 4-10 weeks. If he actually did have a Grade III, then I can't imagine the training staff allowing him to walk off like that because those injuries result in enough instability to create a high likelihood of further injuring other ligaments if the joint was to buckle. I'm holding out for some relatively good news and crossing my fingers that he'll be back in action before Halloween at this point.