Mr. Monti could run as a candidate or endorse a centrist alliance that includes a veteran political party, the Union of Christian Democrats, and Toward the Third Republic, a fledgling civic movement led by the chairman of Ferrari, Luca Cordero di Montezemolo. If Mr. Monti lends his name to the centrists, he is expected to draw moderates from Mr. Berlusconi’s party. Mr. Monti also has the implicit support of the Catholic Church, which is crucial to the survival of any Italian government.

After weeks of wavering, Mr. Monti seems to have decided to stay involved in Italian politics after other European leaders, concerned about the prospect of an increasingly populist Mr. Berlusconi, urged him to stay in the picture.

Last week, members of the European People’s Party, a group of center-right parties across Europe, asked the unelected Mr. Monti to attend a summit in Brussels, which Mr. Berlusconi attended as the head of Italy’s largest center-right party. “I can say that there was massive support from E.P.P. members that Monti should remain at the helm of Italy,” said Kostas Sasmatzoglou, the group’s spokesman.

“It was Europe pushing him to continue,” Mr. Folli, the columnist, said. “Germany already has Hollande,” he said, referring to France’s Socialist prime minister, François Hollande. “It doesn’t want another country to go to the left, to go back on fiscal rigor.”

He added: “It can have Bersani, but Bersani ‘corrected’ and supported by Monti.”

Indeed, if he lends them his support, Mr. Monti and the centrist groupings are not expected to get more than 15 percent of the vote. Mr. Bersani’s Democratic Party is expected to place first, but without enough votes to govern in both houses even if it allies with the smaller Left Ecology and Freedom party. It remains to be seen if the center will take votes away from Mr. Berlusconi or Mr. Bersani.

On Thursday, Mr. Monti was widely perceived to have begun his campaign with a politically calculated speech at a Fiat automotive plant in southern Italy. With Fiat’s chairman, Sergio Marchionne, by his side, he said that Italy needed to stay the course on structural changes. The speech effectively challenged Mr. Bersani, a moderate who will most likely have to tack further left.

Mr. Monti came to power in November 2011, replacing Mr. Berlusconi amid global financial panic. He helped burnish Italy’s image abroad, but effectively raised taxes, worsening Italy’s recession. Although populists have depicted Mr. Monti and his government as a puppet of Europe and the banks, many Italians support him as a needed change from politics as usual.

“I prefer Monti to Berlusconi or any other politician, even if he left us in our underwear,” said Annalisa di Piero, 50, a costume designer and stylist, referring to the tax increases that have left Italians with less in their pockets in the holiday shopping season. “I just paid my property tax, but I still prefer him to these other clowns.”