Sehwag has been promoted as Dhoni's deputy and will do the job in both Test as well as One-Day cricket.
With the departure of Anil Kumble the move appears to be aimed at integrating the leadership group through all formats of the game.
Yuvraj Singh, who was Dhoni's deputy in One-Day cricket has been relieved of those duties to allow him to regain his batting form.
The Delhi opener has in fact been vice-captain under Rahul Dravid and has even led India in a Test match against Sri Lanka at Ahmedabad that India won by 259 runs in December 2005.
He is also the captain of the Delhi Daredevils team in the Indian Premier League (PL) and the Delhi Ranji team.