PHILADELPHIA — A state judge ruled on Monday that a senior Catholic official who was sent to prison for his role in a sexual abuse scandal should be released on bail after an appeals court overturned his conviction for child endangerment.

Msgr. William J. Lynn, the most senior Catholic official to be convicted in connection with charges of sexual abuse of children by clergy members, was granted bail on Monday by Judge M. Teresa Sarmina of the Court of Common Pleas after the conviction reversal last week by the Pennsylvania Superior Court.

The appeals court ruled that prosecutors had provided "more than adequate" evidence that Monsignor Lynn "prioritized the archdiocese's reputation over the safety of potential victims of sexually abusive priests." But it rejected the argument, accepted at the trial last year, that a child welfare law applied to a "parent, guardian or other person supervising the welfare of a child" could be used to prosecute Monsignor Lynn.

Monsignor Lynn, 62, has served about 18 months of a three- to six-year sentence in a Pennsylvania prison. His lawyer, Thomas Bergstrom, said he was expected to be freed on Thursday or Friday while the appeal process plays out.

Bail was set at $250,000, of which Monsignor Lynn must pay $25,000 up front in cash. Judge Sarmina also ordered him to surrender his passport, wear an electronic ankle bracelet and report weekly to law enforcement officials.

Monsignor Lynn, who was not accused of personally abusing children, was convicted in June 2012 on one count of violating the child welfare law by allowing another priest, Edward V. Avery, to live in church buildings where he abused a boy.

As secretary for clergy in the Philadelphia Archdiocese, Monsignor Lynn was responsible for investigating claims of sexual abuse by priests. Prosecutors claimed at his trial that he had placed a higher priority on defending the reputation of the church than on protecting children from predatory priests, a view that was backed by the appeals court's ruling.

In a statement to the court before hearing arguments on bail, Judge Sarmina said she had given the case careful consideration in light of the appeals court's rejection of Monsignor Lynn's conviction and sentence.

"I may have got it wrong," she said. "After all, I'm fallible."

Hugh Burns, the head of the appeals unit at the Philadelphia district attorney's office, opposed bail because the Superior Court's ruling could be reversed and because it is unusual for other types of defendants to be granted bail while their cases are under appeal.

In advance of Monday's hearing, advocates for victims of clergy sexual abuse called on prosecutors to appeal the Superior Court ruling and urged the Philadelphia Archdiocese not to reinstate Monsignor Lynn to a position of ministry.

Judy Miller, who leads the Delaware chapter of the Survivors Network of Those Abused by Priests, handed out pamphlets containing the group's demands to Catholics emerging from a Sunday morning Mass at the Cathedral Basilica of Saints Peter and Paul in central Philadelphia.

"Monsignor Lynn represents thousands of Catholic officials across this country and around the world who have knowingly endangered children," Ms. Miller said. "They have protected criminals and their reputation, and not protected children that were placed in their care."