Shalanda Young, who last month was nominated as deputy director of the Office of Management and Budget, has emerged as a leading contender for the top position at the office, an official familiar with the matter told CNN, as Neera Tanden's confirmation grows even more unlikely.

Young, who was the first Black woman to serve as the staff director of the House Appropriations Committee, has strong relationships on Capitol Hill -- "with Republicans and Democrats alike," the official said. She played a key role in recent budget negotiations, working with GOP Sen. Richard Shelby of Alabama and other Republicans.

Young also doesn't have a Twitter account or a paper trail of incendiary comments, two officials say, which are at the root of Tanden's troubles.

While the White House is officially still standing by Tanden as its choice for OMB director, the prospects for confirmation diminished throughout the day Monday.

White House chief of staff Ron Klain, who is a close friend of Tanden's, is making calls to senators, looking for a Republican to step up and support her, but those efforts have not been successful.

Two other contenders for the OMB post are Ann O'Leary, a former chief of staff to Democratic California Gov. Gavin Newsom, and Gene Sperling, a former director of the National Economic Council, officials said. O'Leary also has long connections with Klain and experience from the Clinton White House, but has far fewer connections on Capitol Hill.

"Shalanda would be a slam dunk to get confirmed," a Democrat close to the White House tells CNN.

This is a breaking story and will be updated.