There had been speculation that Mr Ruto would turn down the new appointment.
A defiant William Ruto on Thursday vowed to remain steadfast in his opposition to the draft constitution despite his transfer from the influential Agriculture ministry.
Answering questions from reporters on whether his supposed “demotion” was punishment for his stand on the draft, the Eldoret North MP said: “If that was the intention, then it will not work.”
Mr Ruto was on Wednesday moved to the Ministry of Higher Education, Science and Technology from the strategic Agriculture docket, much sought after because it supervises more than 30 parastatals and has a bigger budget.
His ally, Mr Charles Keter, was sacked as Energy assistant minister and replaced with Prime Minister Raila Odinga’s loyalist Magerer Lang’at.
Dr Sally Kosgei, who supports the PM, switched places with Mr Ruto.
Mr Ruto said he would take up the new job, possibly to end speculation that he was planning to reject it and resign from the Cabinet altogether.
The speculation was fuelled by his failure to show up at the Higher Education ministry on Thursday morning.
Mr Ruto had instead reported to his former office at Kilimo House early in the morning, collected his personal effects and retreated to his private office in the city centre.
His aides told the Nation that he had spent the rest of the morning meeting his close allies, including former South Mugirango MP Omingo Magara.
He also took some time planning his weekend itinerary, which includes a tour of the South Rift on Friday morning and a meeting in his constituency either on Saturday or Sunday.
He later called a press conference at Kilimo House in the afternoon to announce that he had accepted his new appointment.
“I will be taking over my responsibilities at the Ministry of Higher education shortly,” Mr Ruto announced while flanked by acting Agriculture PS, Mr Kiritu Wamae and senior ministry officials.
Wednesday’s mini reshuffle was seen as the culmination of his supremacy battle with Mr Odinga.
The Presidential Press Service (PPS) bulletin announcing the reshuffle said the changes had been made after consultations between President Kibaki and the Prime Minister.
Asked why he had been moved, Mr Ruto answered: “You should direct that question to the two principals.”
And had he been informed of the changes prior to the announcement?
“Let us not go there,” the minister answered testily.
Pressed on whether he read politics in the changes coming only two months after he was suspended by the PM, only to be reinstated by President Kibaki, he replied: “You live in this country and know what happens, your guess is as good as mine.”
In another development, President Kibaki summoned leaders of his PNU coalition to a meeting at Harambee House.
After the meeting, Deputy Prime Minister Uhuru Kenyatta issued a statement on his position on the draft, saying he supported it.