Curtis McClinton Jr., an official of Amtrak and a former Kansas City Chiefs running back, is expected to be named today to replace Ivanhoe Donaldson as the District's deputy mayor for economic development, according to well-placed D.C. government sources.

Mayor Marion Barry is expected to announce his choice of a successor to Donaldson, his long-time friend and political adviser, today. Late yesterday afternoon the mayor announced that he will make an announcement at a press conference this afternoon.

Annette Samuels, the mayor's press secretary, declined to discuss the mayor's decision, other than to say he will make a "major personnel announcement."

Donaldson, the chief architect of the administration's latest efforts to spur business growth and new jobs, indicated last month that he was anxious to leave city government--possibly to devote full time to private business, including consulting.

A seasoned political operative who ran both of Barry's mayoral campaigns, Donaldson said he also has had conversations with aides to the Rev. Jesse Jackson, who is expected to decide within the next few weeks whether to seek the Democratic presidential nomination.

Neither McClinton nor Donaldson could be reached for comment late yesterday. It is not known when Donaldson plans to step down.

The mayor has known for months that Donaldson intended to leave the government by the end of this year, and he reportedly intensified his search during the past two weeks for a replacement who could command respect in Washington's business community.

Barry told city officials at a cabinet meeting last week that he had narrowed the field to two finalists and would make his decision known shortly.

McClinton, 49, currently the director of real estate marketing for Amtrak, retired from the Kansas City Chiefs in September 1970 after eight seasons as a highly successful running back. He was chosen as the American Football League's Rookie of the Year, and went on to become the Chiefs' fourth all-time yard gainer.

After leaving football, McClinton launched a new career in economic development, first accepting a post as national vice president and executive director for operations of the Black Economic Union, a Kansas City-based group aimed at promoting black enterprise.

A native of Oklahoma, McClinton was a cofounder and director of the Swope Parkway National Bank in Kansas City. He served in the Commerce Department's Economic Development Administration during the Carter administration, and later joined Amtrak.

A D.C. government official who is familiar with McClinton said he would make "an excellent choice" for the deputy mayor's post because "he's very good at economic development" and he has held a "high-powered post" with Amtrak.

Paul Pryde Jr., a private consultant who is under contract to the D.C. Office of Economic Development, also was considered for the deputy mayor post, according to sources.

Pryde is an authority on government enterprise zones and during the 1970s was vice president of Opportunity Funding Corp., a venture capital group.