If the surgery was great and you are all over your rehab you'd be surprised at how quick you can recover. It can happen rapidly but then it begins to taper off. The positive for Maj is he is in ripping condition and has had a few injury setbacks so he knows 100% what is needed and how to be a professional.
Even after knee reconstructions these days you can be on your feet moving around unassisted in no time at all. It's the load bearing stuff that will take Maj some time. He'll be using the AlterG Anti-Gravity Treadmill soonish I'd say.
Hats off to Maj and those in charge of his recovery. Great seeing him there around teammates and smiling.