"I think the likely option is that he will ask Prime Minister Abbas to form the government again," said Saib Uraiqat on Sunday.
The top Palestinian negotiator, Uraiqat, also said Abbas' resignation was still unofficial because he had not yet submitted a formal letter.
But Abbas himself tried to dampen down speculation on Sunday he might reconsider his decision.
Asked whether he would accept the post again, he said: "It's very premature to talk about this right now. My resignation is final."
Abbas offered to resign on Saturday after failing to make headway with the US-backed peace plan known as the road map. He blamed Israel for undermining his position and accused the US of failing to make Israel comply with the road map.
But he has also cited his inability to wrest sufficient powers from Arafat and hostility by some Palestinians towards him as reasons for his decision to step down.
However, Abbas' latest comments appeared to leave open the possibility of a reconciliation with Arafat in the future.
"President Arafat has five options," said Uraiqat in an interview with the BBC.
"Option number one is to accept the resignation, which he has not done yet because he (Abbas) has to send the written letter.
"Secondly, he can reject the resignation. Thirdly, he can begin consultations, which he began last night.
Arafat (C) with Ahmad Quraya
(L) at Sunday's Fatah meeting
"Fourthly ... he can accept the resignation and ask Abu Mazin (as Abbas is also known) to form the government again. Fifthly, he may accept the resignation and ask somebody else.
"I think President Arafat is weighing these options and I think the likely option is that he will ask Prime Minister Abbas to form the government again."
Uraiqat stressed the Palestinian leadership was still interested in the US-backed road map.
"We want to keep the American administration engaged, we want the quartet to revive its role in terms of maintaining the road map on the table."
Uraiqat's comments came as Arafat chaired a meeting of the central committee of his Fatah movement at what remains of his offices in the West Bank city of Ram Allah. Fatah is the biggest bloc in the Palestinian Liberation Organisation (PLO).
Suddenly back at the centre of Palestinian politics despite Israeli and US attempts to sideline him, Arafat was then due to meet the executive committee of the PLO to discuss the appointment of a prime minister.
Besides members of the central committee, most of 63 Fatah deputies in the Palestinian parliament attended the meeting in Arafat's damaged headquarters.
Some deputies told AFP Arafat would ask Abbas to form a new government although others said Abbas was unlikely to agree.
If Abbas does not return to his post, the man regarded as the most likely successor is Ahmad Quraya, the speaker of the Palestinian parliament and one of the architects of the 1993 Oslo peace accords.
"He (Quraya) is a very strong candidate to be prime minister," said Foreign Minister Nabil Shaath after the Fatah debate, "but in the meeting we did not discuss any names."