I really wouldn't expect it to be clear, which is probably a good thing. If it were clear cut, it would probably be a serious and season-ending injury. Lesser injuries have a lot of variability in terms of recovery time.
As a physician, I couldn't even make a guess as to how long Mayo will be out without seeing his MRI images and examining him. It sounds like the injury was isolated to his MCL, which is good, and was not a tear, which is also good. A lot depends on individual rate of healing from injury, and also how cautious the Pats are about bringing him back. I wouldn't expect a consensus even among orthopedic surgeons with backgrounds in sports medicine who have access to all the data. Plus, I'm sure BB would rather wait a wekk or two and have a fully healthy Mayo ready for the stretch run than rush him back too early if there is any question whatsoever.
My best guess is that we won't see him for at least a month and probably not until after the bye week, but it's just a guess, and I doubt anyone knows at this time how quickly he will recovery. I think the safest thing is not to count on him too soon.