The romantic view would be he returns from injury, he's able to contribute meaningfully a few times off the bench or even starting on the way to a major trophy success, and then we sell.
The unromantic and rather grim view would be any version of that which doesn't work out in any way.
If Havertz is recovering properly I'd be happy if we somehow moved Jesus on cheaply in winter to get fit for the World Cup. If not perhaps we're stuck with him.