Out the next two games. That's awful to hear, but if we can get him close to 100% for Ohio State, nothing should be lost on the bottom line. With this news, his performance against UNC is extra impressive. Get well soon 'Gody!
EDIT: I haven't heard any other news sources backing up that 2 game prediction, so it could be more. I'm no doctor, but if his disease is bacteria-based it could be treated with antibiotics and be done in a week. Viral based pneumonia is more serious, perhaps keeping him out up to a month.
No matter what, I agree with Coach Brey's assessment that Luke's health is the biggest priority. Though Ohio State might be a difficult game without him, the Irish will have more opportunities for other players against non-conference cupcakes.