Nigeria's vice-president, a leading contender in April's presidential polls, has interrupted his campaign to go to London after damaging his knee.
Atiku Abubakar has stopped running - temporarily
Atiku Abubakar fell off his running machine and was then flown to the UK on Sunday, says his spokesman Garba Shehu.
"It was not a very serious injury, so he is expected back within days," Mr Shehu told the BBC News website.
On Sunday, ruling party candidate Umaru Yar'Adua returned to Nigeria from an emergency overseas health visit.
Mr Shehu says Mr Abubakar is being treated at the London Bridge Hospital for a torn tendon.
Mr Abubakar, a former ally of President Olusegun Obasanjo fell out with the president after he publicly opposed moves to change the country's constitution to give the president a third term.
Mr Obasanjo's political loyalists then forced Mr Abubakar out of the People's Democratic Party and he joined the opposition Action Congress on whose platform he is running for president.
Mr Abubakar's ill-health prompted President Olusegun Obasanjo to forget his public spat with his deputy - as he allowed him use of a presidential jet for the London trip.
The PDP presidential campaign was thrown into confusion last week when Mr Yar'Adua collapsed and was flown to a German hospital for medical tests.
Despite a fallout, President Obasanjo lent him his presidential jet
The 55-year-old former chemistry teacher is the frontrunner to win the election and has previously suffered from a kidney illness.
His collapse prompted speculation that he could be replaced as the PDP's candidate. The polls should become the first transfer of power in Africa's most populous country from one elected leader to another since independence in 1960.
Despite being Africa's largest exporter of oil, Nigeria remains poor with over 70% of its population living on less than $1 a day.
Corruption and mismanagement have hobbled Africa's most populous nation where most basic services, including decent health care are absent.
Although rich Nigerians routinely travel overseas for even the most basic heath issues, some Nigerians are saying the ruling party in government has failed to develop health care in the country and should be voted out of power next April.
"Look, I am an ordinary man, but I have a vote," says Tunde Akunbi, an Abuja taxi driver.
"If Yar'Adua and Atiku are going abroad for mere medical check-ups and minor knee injuries, what does that say to President Obasanjo? It says, his government has failed in health care. I can't vote PDP."