The drama surrounding the future leadership of the ultra-Orthodox Shas party has reached a fever pitch and the general expectation is that a revolution is at hand: Aryeh Deri, who withdrew from politics to serve time in prison for corruption, may now return to the party's helm.

In the next 48 hours, the Shas Council of Torah Sages will convene to finalize the decision over who will lead the party into the election: Deri or party leader and Interior Minister Eli Yishai.

It was reported on Monday that Deri's efforts to reinstate himself as the head of the Shas party have borne fruit and he will likely take the number one position on the party's Knesset list, while Yishai will likely be given the senior ministerial position in the party.

"The balance of power at the home of the rabbi [Shas spiritual leader Rabbi Ovadia Yosef] is such that there are aides, children and family seeking to incorporate Deri in the number one position, but on the other hand, the rabbi is totally committed to Yishai," said one senior Shas official.

Before Monday, Yosef reassured Yishai twice, telling him he had nothing to worry about. But on Monday, the rabbi asked Yishai a question on the matter that indicated to Yishai that the rabbi was seriously considering reinstating Deri at the party's helm.

"There is a commotion over there," the official said. "People are going in to see the rabbi, talking to him, and sometimes convincing him and sometimes failing to convince him. Ultimately, the decision is only up to the rabbi."

Pressure is also being exerted on members of the Council of Torah Sages, as each side maintains dialogue with the rabbis. Some of the council members, such as Rabbi Shalom Cohen for example, are doing little to hide their support for Deri. On Friday, Deri met with another council member, Rabbi Shimon Baadani, to discuss the political situation. Baadani later told his pupils that Yishai was the best and most loyal Shas leader and that he must retain his post, with Deri and current number two Ariel Attias supporting him.

But according to sources at the rabbi's house, this time the decision will not be made by the council. "The rabbi [Yosef] may listen to their opinions, but ultimately he will make the decision alone. He will apparently disperse them, think some more, and then decide. The rabbi is under tremendous pressure. He is committed to Eli Yishai but his affections, and history, lie with Deri. He also understands that Deri will bring the party more seats, and he is taking everything into consideration. But we really don't know what he will decide. This is certainly one of the most dramatic events we have known," said a source at the rabbi's house.

Deri, who was among the founders of Shas in 1984, was convicted of accepting bribes, fraud and breach of trust. He was sentenced to three years and was assigned moral turpitude, which prevented him from running for office for seven years.

Meanwhile, in other pre-election news, additional drama was unfolding in another camp — Kadima. Associates close to former Prime Minister Ehud Olmert, also convicted of breach of trust, said the chances that he would run in the upcoming elections were about 50:50.

According to the associates, Olmert has reviewed poll numbers indicating that if he were to run for office together with former Kadima Chairwoman Tzipi Livni and current Kadima Chairman Shaul Mofaz, he could win between 24 and 26 seats. He also learned, they said, that former Israel Defense Forces Chief of General Staff Lt. Gen. (ret.) Gabi Ashkenazi would be key in eliciting votes.

They said further that if Olmert decided not to run, Livni would announce the establishment of a new party, with her at the helm. In such a case, experts surmise that Mofaz will not join her.

Livni's associates suggested that in such a scenario, Olmert would throw his support behind Livni, rather than Mofaz. Olmert and Livni were scheduled to meet on Tuesday to discuss the issue.