The network said it would name a replacement for Tom Touchet, the show's executive producer, on Wednesday. Touchet has had the job since November 2002.
"Today" hasn't spent a week out of first place in the ratings, but NBC's position of unchallenged dominance in the morning has eroded. Its margin over second-place "Good Morning America" is 662,000 viewers this season, roughly half what it was last year.
On a handful of individual days, like the Monday after Pope John Paul II died, "Good Morning America" has even beaten "Today."
NBC's morning team of Katie Couric, Matt Lauer, Al Roker and Ann Curry, which the network advertises as "America's First Family," remains intact.
Touchet was not immediately available for comment, said an assistant who answered his phone on Tuesday.
In addition to its news report, "Today" has launched several segments hugely popular with viewers - an outdoor concert series that celebrates its 10th anniversary this year, annual weddings planned by viewers and Lauer's road trips around the world.
The architect of the show's current success, former executive producer Jeff Zucker, has risen to chief of the NBC Universal Television Group, but retains a keen interest in the show that launched him.
NBC's expansion of "Today" to three hours in the morning has also been a financial success, but is less well regarded creatively.
It's also said to be a volatile place backstage. One gossip column report a few weeks ago had Touchet slamming a glass door there with such force it shattered.
By David Bauder