Look at Derrick Rose, he held out for a long time and ended up getting re-injured after his torn ACL.
I think the sooner you get back to real game scenario after the doctor cleared you, the better it is to adjust to normal game intensity. there is the a psychological hurdle that you have to overcome the brain would still try to overcompensate to protect the previously injured knee, and that can lead to re-injury when it throws your body out of balance again. The sooner it is to get back in game shape, the more time he gets to re-adjust his brain to playing like the knee is normal again.