Indianmandarins has reliably learnt that an ADG post has been kept vacant in the CBI which may be filled by in-situ promotion, but it may take time. The CBI has three sanctioned posts of Additional Director General. Two are occupied by 1984 batchmates Rakesh Asthana (IPS:GJ) and Y C Modi (IPS:AM), while one is kept deliberately vacant for the last few months.
It's learnt that immediately after 1986 batch of IPS officers are empanelled, M Nageshwara Rao (IPS:1986) will be in-situ elevated as ADG, CBI. He was appointed Joint Director of the CBI on 6 April 2016.