Philadelphia District Attorney Seth Williams this morning announced a series of shifts among his top administrators including the hiring of a former state prosecutor to head the unit in charge of grand jury probes and an open-ended medical leave of absence by his No. 1 deputy.

In a news conference at his Center City offices, Williams described the changes as part of a renewed effort to attack the problem of government and city corruption.

Citing muckraker Lincoln Steffens's famous description of Philadelphia as "corrupt and contented," Williams said that "a century later I am working to change that" by bringing former state prosecutor Patrick Blessington into the office.

Williams praised McGettigan's work in the office's number two position at reorganizing the way in which cases are charged and prosecuted. Williams said McGettigan will next week undergo long-delayed hand and knee surgery requiring extended rehabilitation.

Williams disputed parts of a story in today's Daily News, which quoted sources as saying First Assistant District Attorney Joseph McGettigan had quit after serious policy disputes with him.

Williams, however, did not dispute that he and McGettigan had disagreed on issues, as he said he had with any number of other employees.

"I'm sure there are a few people who have been angry with me," Williams said.

Williams said he would discuss after McGettigan's medical leave ends whether, and in what job, the former first-assistant might want to return.

In the meantime, Deputy District Attorney Edward McCann, a veteran homicide prosecutor whom Williams promoted to the chief of the trial division, becomes acting first assistant district attorney.

Blessington is no stranger to the District Attorney's office. He first joined it in 1986 after graduating from Villanova Law School and rose to the post of chief of the juvenile unit.

In 1997, Blessington left the office to join the Pennsylvania Attorney General's office, where he was a senior deputy attorney general before rejoining the Philadelphia prosecutor's office on Wednesday.

Blessington will replace another veteran of more than 20 years in the District Attorney's office, Christopher Diviny, who on Monday will join the U.S. Attorney's office in Philadelphia.

Blessington will report directly to former federal prosecutor Curtis Douglas, who Williams hired and named the deputy for investigations.

Contact Joseph A. Slobodzian at 215-854-2985 or jslobodzian@phillynews.com.