Gusau's removal was not unconnected to the controversial 2016 budget, which was describedGovernor Ayodele Fayose of Ekiti State as a national embarrassment.
Abdullahi is a fellow of the Certified National Accountants of Nigeria, and a banker of repute with experience in managing public finance.
According to Premium Times which cited a Presidency source, Gusau's removal was not unconnected to the controversial 2016 budget, which was described by Governor Ayodele Fayose of Ekiti State as a national embarrassment.
The online new portal said Buhari believed Gusau, who was appointed to the office on August 18, 2015 failed to effectively deliver on his mandate.
He was supposed to serve a four-year tenure, but cut short in less than six months after his appointment.
The new Director-General (Budget) is expected to work with the Minister of Budget and National Planning to efficiently deliver on the mandates of the Budget Office of the Federation, a statement by the presidency said.
The President also appointed Ben Akabueze as the Special Adviser on Planning to the Minister of Budget and National Planning.
Akabueze is the immediate past Commissioner for Economic Planning and Budget in Lagos State. He has worked in senior management positions in Citi Bank, Fidelity Bank, United Bank for Africa, NAL Merchant Bank, Sterling Bank and BIA Consulting Limited, among others.
He is Fellow of the Chartered Institute of Bankers; Fellow, Institute of Credit Administrators and Honorary Fellow, Chartered Institute of Bankers.