I feel like this comes up in every Kings thread.
Disclaimer: I was a sports therapist for a decade, 'retired' this year. An Achilles injury will take 6-8 months to heal, usually a bit less for pro athletes. Rudy entirely tore his Achilles', which is better than a partial tear because its easier to stabilize when you can surgically repair the entire tendon instead of having to maintain a part of the tendon while repairing the ruptured part.
Barring a setback, Rudy Gay will play in 2017, and it will be for the Kings. There are financial reasons (0% chance he sits out another full season going into free agency) but medically speaking, the idea that he wouldn't be ready physically has been thrown about a lot, and is simply not true. Nor is the idea that it will take X amount of time to heal 'correctly' and return to prior form. The only hurdle after recovery, assuming he sticks to a quality rehab regiment and minimizes scar tissue, is a psychological one. And those vary greatly person to person.