Ferrari say they are “still working on collecting evidence” on the incident.
But they declined to confirm that their appeal had been formally withdrawn.
Ferrari is believed to be considering challenging the penalty via a different approach – a right to review the incident.
Vettel left the track at the Turn Three/Four chicane when under pressure from Hamilton on lap 48 of the race on Sunday.
He rejoined the track on the exit of the corner and swept across to the wall on the outside. Hamilton, who had half his car alongside the Ferrari, hit the brakes to avoid crashing into Vettel.
Race stewards decided the four-time world champion had “rejoined the track in an unsafe manner and forced (Hamilton) to take evasive action to avoid a collision”.
A number of sections of the FIA’s international sporting code potentially govern the incident between Hamilton and Vettel.
One says: “Manoeuvres liable to hinder other drivers, such as deliberate crowding of a car beyond the edge of the track or any other abnormal change of direction, are strictly prohibited.”
Another says that any driver rejoining the track can only do so “when it is safe to do so and without gaining any advantage”.
Another adds: “It is not permitted to drive any car unnecessarily slowly, erratically or in a manner deemed potentially dangerous to other drivers at any time.”
But the rules also dictate that certain penalties – of which this is one – are not subject to appeal.
So seeking a right to review could circumnavigate the technical restrictions on their ability to appeal.
Ferrari has until about 22:00 BST on Thursday to formally give notice that they are withdrawing the appeal.
Any public announcement of their decision and route forward is likely to come after that.