By 27 December -- when the nomination groups are formally announced -- there may be fewer. And by the 19 March vote, fewer still.
One challenger expected to stay on the ballot is Alyaksandr Milinkevich, the candidate of the united opposition forces.
Milinkevich announced his intention to enter the race in early October. Since then, he has conducted a grass roots campaign to build a support base, often going door-to-door in an attempt to meet potential voters.
Milinkevich is better prepared than most -- his nomination group will have far beyond the minimum 100 people required for registration. Still, he told RFE/RL's Belarus Service the new, early date for the presidential vote is a setback nonetheless.
"To include people in your nomination group, you need to talk with each of them [to make sure] they won't resign afterwards," Milinkevich said. "We have had our list of activists for a long time already. This work is being done now, [but] the group will not be as large as I had expected. I thought that by the summer we could have as many as 10,000 people. We will have fewer people [now]. However, they will be numbered in thousands, not hundreds."
Few observers were surprised by the decision to move up the date of the election -- or that the move was announced one day after Lukashenka met with his counterpart, Russian President Vladimir Putin.
Russia, wary of a new "color revolution" in its post-Soviet backyard, is determined to see Lukashenka remain in power. It is also eager to gain greater control of Belarusian gas pipelines -- something it can do best with a pliable ally in the presidential office.
In return, it is providing Belarusians with some of the cheapest natural gas in the Commonwealth of Independent States -- while very publicly subjecting Orange Revolution Ukraine and Rose Revolution Georgia to fierce price hikes.
Lukashenka orchestrated his own reelection bid with a public referendum in October 2004. The poll, which was widely criticized in the West, allowed him to seek an unprecedented third term.
Few expect him to lose. But Milinkevich and other potential candidates -- like Syarhey Haydukevich, leader of the Belarusian Liberal Democratic Party -- hope to use the election to draw attention to what they say are Belarus's growing ranks of the politically and socially discontent.
"I will gather a nomination group as I have promised; I'm obliged to show that [my party] has the necessary structures. But I haven't made a decision yet. If it turns out that the situation isn't serious, I won't take part [in the election]," Haydukevich said.
Candidate hopefuls also include Alyaksandr Kazulin, leader of the Belarusian Social Democratic Party (Hramada); Zyanon Paznyak, the exiled leader of the Conservative Christian Party; and former General Valery Fralou, who as an opposition lawmaker staged a hunger strike in 2004.
They have until 23 December to turn in their nomination group lists. Those that manage to qualify for registration will be announced on 27 December. Then each group will have just four weeks (29 December-27 January) to gather at least 100,000 signatures needed for a candidate to be formally added to the ballot.
The early election date has other potential consequences as well. Some observers have suggested the earlier date is meant to keep Belarus off the radar of the international community, which will be focused on Ukraine, where parliamentary elections will be held just one week later.
It is not yet certain if international election monitors will be on hand for the Belarusian ballot. The Lukashenka regime has accused foreign organizations of seeking to influence the outcome by providing funds and other aid to the opposition.
Mikalya Lazavik, secretary of the country's Central Election Commission, told RFE/RL's Belarus Service that monitors will be present -- as long as they have no political agenda.
"If they want to come here as observers, and not as participants in the political process, then why not? We're always open to cooperation," Lazavik said.
Both the European Union and the United States have called for the vote to be free and fair, and pledged, if it is not, to toughen sanctions against Lukashenka's administration.
(RFE/RL's Belarus Service contributed to this report.)