Naijaparry reports that the ruling party had endorsed Senator Ovie Omo-Agege (APC-Delta-Central) for the position.
The party's National Publicity Secretary, Lanre Issa-Onilu, made this known in a statement on Monday in Abuja, Nigeria's capital.
According to the statement, the decision to adopt the senator was taken at an emergency meeting of the NWC.
However, Kalu announced his withdrawal from the race on Tuesday morning, citing the position of the APC leadership as the reason for his decision.
The former governor tweeted: "I decided to throw my hat into the ring to contest for the position of Deputy Senate President @NGRSenate after wide consultations with stakeholders especially my political associates, friends & colleagues (returning senators & senators-elect).
"However, I use this medium to announce my withdrawal from the race in the interest of the APC @OfficialAPCNg & Nigeria at large. I contested & won election as a Senator on the platform of the APC @APCNigeria & as such, I cannot go against the decision of my party.
"The party, I am optimistic will consider the South East for other principal positions in the Senate @NGRSenate & House of Representatives @HouseNGR for the sake of national unity. The South East should be ably & well represented at the top hierarchy of the 9th national assembly.
"The 9th national assembly will work harmoniously regardless of party affiliations to ensure that the executive & judiciary arms of government are complemented in a bid to build a prosperous Nigeria."
