M Nageswar Rao is only an interim arrangement until the Central Vigilance Commission (CVC) decides on its probe involving both, CBI spokesperson Abhishek Dayal said.
Verma has approached the Supreme Court seeking quashing of a late night government order of October 23 which divested him and his bete noire Asthana of their powers and Rao was handed over his duties and functions.
In the unprecedented shake-up in the CBI's 55-year-history, both Verma and Asthana were sent on leave.
The Centre had taken the decision following a recommendation from anti-corruption watchdog CVC, which unanimously felt that Verma was creating "wilful obstruction" in functioning of the Commission which was looking into complaints of Asthana against the CBI director.
After the mid-night drama which benched him, Verma approached the apex court contending that divestment of his powers "overnight" amounts to interference in the independence of the agency.
He said as the CBI is expected to function completely independently and autonomously, there are bound to be occasions when certain investigations into high functionaries do not take the direction that may be desirable to the government.
Verma also contended that the Centre and the CVC's move was "patently illegal" and such interference "erodes" the independence and autonomy of the Central Bureau of Investigation (CBI).
The CBI, which refused to comment on the question about the status of Verma and Asthana, Wednesday issued a clarification saying, "Alok Verma continues to remain Director of CBI, Asthana remains Special Director."
"M Nageswar Rao is looking after duties and functions of the Director in the interim period till the time CVC looks into allegations and counter allegations," the CBI spokesperson said.
The petition of Verma and NGO Common Cause, represented by senior lawyer Prashant Bhushan, against the decision of the Centre to divest him of his powers is coming before the Supreme Court Friday.
The matters are listed as item number 41 and 42 in the supplementary list for admission.