Gayle King, Charlie Rose and Erica Hill on “CBS This Morning.” (John Paul Filo/CBS)

In the most recent week for which Nielsen ratings are available — the week of July 16, “CBS This Morning” averaged about 2.3 million viewers and 877,000 viewers in the 25-54-year age bracket, a.k.a. the currency of news programming.

That’s about half as many viewers as ABC’s “Good Morning America” scored the same week. It’s also short of the ratings “The Early Show” had been averaging during the 2011-12 TV season until it got shuttered in January of ’12 to make way for “CBS This Morning.”

CBS News has figured out what is the problem.

The problem is — Erica Hill.

CBS News announced Thursday it will swap out co-host Hill for White House Correspondent Norah O’Donnell on the show headlined by Charlie Rose and Gayle King.

O’Donnell, who has been CBS News’ Chief White House Correspondent since June 2011, will leave the White House to assume her new role, but will continue as the principal substitute anchor for “Face the Nation.” She also will continue to report for all CBS News broadcasts and platforms.

O’Donnell will join Charlie Rose and Gayle King in the fall.

And what of Hill, who has been Rose and King’s co-host since the show’s launch? She’s in a state of “in discussions” about a “new role,” CBS News said Thursday morning.