Reg Murphy, who helped bolster the Sun newspapers' dominance of the Baltimore area during the past decade, said yesterday he is resigning as publisher and chief executive officer of the newspapers.

Murphy will briefly become chairman of the morning and evening papers and then leave the papers within a few months.

Murphy, 56, said he had been asked by the Sun newspapers' parent company, Times Mirror Co. of Los Angeles, to stay on the job, but asked to leave after nine years as head of the papers. Murphy said he intended to finish a political novel he has been writing and would "look for his next challenge."

Times Mirror, which also owns the Los Angeles Times and Newsday in New York, yesterday named Michael J. Davies to replace Murphy. Davies, 46, has been editor and publisher of the Hartford Courant since 1983. The Courant is also owned by Times Mirror.

Under Murphy, the Baltimore Sun and Evening Sun consolidated their hold on their local newspaper market and in 1985 won Pulitzer prizes for explanatory and feature writing. The papers' business fortunes were greatly boosted by the closure of Hearst Corp.'s Baltimore News American in 1986.

Times Mirror bought the Sun papers, which have morning circulation of 233,539 and evening circulation of 167,637, from A.S. Abell Co. for $450 million immediately after the News American's demise.

Newspaper analyst John Morton said Murphy leaves both Sun newspapers in profitable condition despite industry-wide declines in advertising. However, Morton said Murphy has acknowledged previously that he wanted to combine the two papers into a single morning paper.

While the Evening Sun is in the black, the paper's circulation has not grown much in the past 10 years. Evening newspapers, traditionally strong among blue-collar workers, have been hurt by competition from TV newscasts and changes in the composition of the work force. The density of afternoon and early evening traffic has also made it more difficult for newspapers to deliver evening papers to homes in distant suburbs.

Davies said he was joining the papers without preconceptions or a detailed strategic plan. He said of the Evening Sun, "... Viscerally, I would love to have morning and afternoon papers {in Baltimore} into the next century. Whether that's possible or not, we'll have to see."

During his tenure in Hartford, Davies's key innovation was the introduction of several new daily "zone" editions -- special sections filled with regional editorial content and advertising -- that fortified the paper's statewide presence.

Davies also edited the defunct Kansas City Times and Louisville Times, and the Louisville Courier-Journal. The Courant, during his tenure, was sometimes at the center of controversy over its coverage of local issues.

In 1984, Davies in his role as Courant editor wrote a column apologizing for the "snide tone" of a news analysis of Hartford-based Coleco Industries Inc. and later reproached some reporters for their tough coverage of other businesses.

A 1987 book by former Courant staff writer Andrew Kreig, "Spiked: How Chain Management Corrupted America's Oldest Newspaper," alleged that the 226-year-old Courant had engaged in a variety of deceptive and unethical practices. The newspaper has denied the allegations contained in the book.