In a highly unusual move, Defense Secretary Donald H. Rumsfeld (search) has selected a retired four-star general to become the next Army chief of staff, senior defense officials said Tuesday.

The officials, who spoke on condition of anonymity, said the selectee is Peter J. Schoomaker, who retired from the Army after commanding the U.S. Special Operations Command from 1997-2000.

The choice, which has not been publicly announced and is subject to confirmation by the Senate, may raise some eyebrows inside the military because it is rare for a defense secretary to bypass senior active-duty generals in favor of a retired officer to be the Army's top general.

The current chief of staff, Gen. Eric Shinseki (search), is retiring Wednesday.

Because no successor will have been nominated and confirmed by then, the vice chief of staff, Gen. John Keane, will temporarily assume Shinseki's job when he departs, officials said.

Rumsfeld had tried to persuade Keane to take the top job but he declined for family reasons, officials said.

Schoomaker began his Army career in 1970 as an armor officer but switched to the secretive world of special operations in the late 1970s. He graduated from the University of Wyoming, where he was a star football player, and served with a variety of armor and cavalry units.

From 1975-76, he completed the Marine Corps amphibious warfare course and in February 1978 joined the Army's 1st Special Forces Operational Detachment, now known as the highly secretive Delta Force (search that specializes in counterterrorism missions.

He later was commander of the Army Special Operations Command and the Joint Special Operations Command at Fort Bragg, N.C.