Dwight S. Cropp, a high-ranking assistant to Mayor Marion Barry, is considering leaving the mayor's staff to accept an administrative post with the University of the District of Columbia, according to sources.

Cropp, 44, the secretary of the District of Columbia, acknowledged yesterday that he had received a "very attractive offer," but declined to confirm that he was negotiating with UDC officials.

"The mayor is aware of the offer," Cropp said. "The mayor never intended people to delay their career development."

If he accepts the job, Cropp will become the fourth top official in Barry's administration who has left government or plans to leave by the end of the year.

Elijah B. Rogers resigned this spring to take a job with a private accounting firm. Corporation Counsel Judith Rogers recently was confirmed as a judge on the D.C. Court of Appeals. And Deputy Mayor Ivanhoe Donaldson intends to leave his post by the end of the year.

Cropp and his wife, Linda, a member of the D.C. school board, have been longtime supporters of the mayor. Cropp has been the city's executive secretary since Barry first took office as mayor in January 1979.

He has been with the D.C. government for 18 years, first as a public health investigator, then as a public school teacher. He also worked for several years with the D.C. school superindent's office and the board of education.

Cropp, a pleasant, soft-spoken man, has served as Barry's principal adviser on education. A National Urban Fellow at Yale University in 1970, Cropp has published numerous articles on education, public administration and management.