Factbox: Potential Nigerian presidential candidates

LAGOS (Reuters) - Nigeria's former military leader Ibrahim Babangida on Monday became the first major politician to announce he will run for president next year.

The race for president of Africa's most populous nation is expected to be wide open since many believe the ailing President Umaru Yar'Adua, a northerner, will not seek re-election.

Acting President Goodluck Jonathan, who is from the south, has assumed executive powers for Yar'Adua, who remains too sick to govern and has been out of the public eye since November.

But Jonathan is unlikely to stand in 2011 because of an unwritten agreement among the political elite that the presidency rotates between the north and south every two terms.

Following are some of the northern names being mentioned within the PDP and in Nigerian media as possible successors to Yar'Adua:

IBRAHIM BABANGIDA

Babangida, a 68-year-old northerner from Niger state, seized power in 1985 in a bloodless coup, ruling the oil exporter for nearly eight years.

Babangida was forced from power after cancelling an election generally regarded as fair, and this still colors his political reputation. His departure ushered in another army coup and the dictatorship of Sani Abacha.

Even though the next president is expected to serve only one term before making way for a southerner, analysts say his age could also be a concern to voters who have seen Yar'Adua's health fail in mid-term.

Babangida said he would significantly reduce the powers of the federal government if elected, and transfer them to states and local councils.

ALIYU GUSAU

Gusau is a retired general and former National Security Adviser to Yar'Adua's direct predecessor, Olusegun Obasanjo, and remains a powerful kingmaker in the ruling party.

Gusau was the main contender alongside Yar'Adua to be the candidate of the ruling PDP in the 2007 election, coming second in the primaries. He is seen as a favorite among powerful northern generals.

SULE LAMIDO

Lamido, the populist governor of the backwater state of Jigawa, was foreign minister under Obasanjo. He is said to enjoy the support of the former president and of Jonathan, whom he backed to come to power.

But analysts say Lamido is seen by his northern kinsmen as politically weak and too heavily influenced by Obasanjo, who is unpopular for helping to bring Yar'Adua to power despite knowing of his health problems.

ABBA RUMA

Ruma was Yar'Adua's agriculture minister and has been his confidant since serving as governor of the remote northwestern state of Katsina. He was also education minister under Obasanjo.

Ruma is a member of Yar'Adua's inner circle, which includes Yar'Adua's wife Turai, and is seen as one of the candidates most likely to protect the interests of Yar'Adua and his allies.

BUKOLA SARAKI

Saraki, the ambitious governor of the central state of Kwara, is another close confidant of Yar'Adua. He is a trained medical doctor and was director of Societe Generale Bank (Nigeria) for 10 years up to 2000, when he took up a post as special assistant to the president on budgetary matters.

Saraki, who is serving his second and final term, is the chairman of the Governors' Forum, a powerful grouping that is influential in selecting presidential candidates.

He is also close to James Ibori, the former governor of Delta state and one of Nigeria's most influential politicians, who was instrumental in Yar'Adua's rise to power.

He is the son of Kwara state's political "godfather" Olusola Saraki, who vied for the presidency in the 1990s and is an influential senior figure in the PDP.

MAHMUD YAYALE AHMED

Yar'Adua appointed Yayale secretary to the federal government in 2008, a powerful position that co-ordinates between ministries and the presidency. He had previously served as defense minister.

Yayale was also head of service under Obasanjo, the most powerful civil servant, but is reported to have fallen out with the former president.

ISA YUGUDA

Yuguda, governor of the northeasterly Bauchi state, is Yar'Adua's son-in-law and a member of his kitchen cabinet. He spearheads the president's economic think-tank, set up to steer Nigeria through the global economic downturn.

Once a bank managing director, and aviation minister during Obasanjo's first term, he was among those tipped to take over as governor of the central bank earlier this year.

Yuguda won the 2007 Bauchi governorship election on the platform of the opposition All Nigeria People's Party (ANPP), but has since switched to the ruling party.

JIBRIL AMINU

Aminu, a second-term senator from northeast Adamawa state, served as oil minister under Babangida, and narrowly missed becoming vice president in 1999 when Obasanjo selected Atiku Abubakar instead.

The erudite politician was compensated with an appointment as ambassador to the United States from 1999-2003.

Though Aminu also enjoys Obasanjo's support and that of the National Assembly, he is disadvantaged because he is in his 70s and is known to have medical problems of his own. (Editing by Randy Fabi and Kevin Liffey)