DALLAS (AP) _ Bill J. Powell, senior vice president-circulation of the Dallas Times Herald, has been named vice president-circulation of the newspaper's parent company, MediaNews Group.

The appointment was announced Wednesday by William Dean Singleton, chairman of Dallas-based MediaNews Group.

Art Wible, publisher of the Times Herald, also announced two executive changes at the newspaper.

Thomas E. Rice, senior vice president-operations and human resources, will take on the added responsibilities of the circulation and transportation departments, Wible said.

Richard R. Seibert, circulation manager of the Fort Lauderdale News and Sun-Sentinel Co., will join the Times Herald in July as vice president-circu lation. Seibert will report to Rice.