It's been FOUR years since I've sprained/torn my left ankle, and I still cannot run. So at least 4 years, if you don't tear it again.
Not everything heals without surgery. Surgery to pin the tendon back onto the bone.
So you cannot run! What's the big deal? You only drop a level in singles tennis, and in doubles, it barely makes a difference.
So you can't be a track star, or run marathons. No biggie. You can still ride a bicycle and go to work, play some tennis, and enjoy your life.