* Sabahi came 3rd in 2012 election
* Sisi seen as favourite for vote (Adds Abol Fotouh position)
CAIRO, Feb 8 (Reuters) - Egyptian leftist politician Hamdeen Sabahi announced on Saturday he would be running for the presidency in a forthcoming election, enlivening a race that army chief Field Marshal Abdel Fattah al-Sisi is widely expected to win.
Sabahi came third in the 2012 election won by Mohamed Mursi of the Muslim Brotherhood, who was deposed by the army in July following mass protests against his rule.
"My personal decision as a citizen is to run for the coming presidential elections," Sabahi said in a public address to supporters. "Hamdeen Sabahi's battle is the battle of the revolution," he said.
Sabahi, 59, built a big following during his campaign for the 2012 election, using a popular touch to beat candidates with better funded campaigns.
The dearth of candidates ahead of this election provides a stark contrast to the 2012 vote, the first time Egyptians were allowed to freely choose their head of state.
Abdel Moneim Abol Fotouh, a moderate Islamist who came fourth in that vote, has said he does not plan to run, saying the current circumstances are neither free nor democratic.
Members of his party were detained in January while campaigning against a new constitution passed in a referendum.
Since Mursi was deposed, hundreds of his supporters have been killed and thousands arrested in a state crackdown on the Brotherhood, Egypt's best organised party until last year.
Some of Egypt's best known secular dissidents have also been jailed in recent months for protesting without permission.
Sisi, 59, seems certain to win the election, though he has yet to formally declare his candidacy.
He is popular among many Egyptians who were relieved to see the end of Mursi's rule and who see him as the kind of strong leader needed to stabilise a country in crisis.
He has been lionised by state and privately owned media.
The election is expected as early as April.
Hassan Nafaa, a professor of political science at Cairo University, said Sabahi's decision could encourage more candidates to run, adding that a more competitive vote would bolster a Sisi presidency.
"It is in his favour to win by 60 percent rather than 90 percent," he said. (Reporting by Ali Abdelatti/Tom Perry; Writing by Tom Perry; editing by Ralph Boulton)