This will be a wild guess since I have literally no clue what his medical or conditioning situation is, let alone his mental state, so absent any information on that side I will go conservative and say I am not expecting to see him until next season. I will be happy if he proves me wrong, even though I'm only expecting him to be 50% of what his capability is when he returns.
If he returns and we are in the thick of a playoff run, I think the expectations on him by casual fans will be immense and unfairly so, and they will be disappointed when he's not "peak Tatum", so in a way I hope he skips all that and returns next season.