"He hopes to return," Nunery said Thursday, "and we hope he returns."
Parents expressed dismay that West's leadership team was being reshuffled again.
Carla Jackson, who has a son in 11th grade, was surprised and frustrated to hear of another principal change.
"We can't get a foundation until we get some stable people," she said. "My parent involvement depends on knowing the principal. This is something we have to work together on. I was just getting to know this one."
Nunery and other district officials have been giving extra attention to West this fall to improve academics, deal with complaints about organizational issues, and manage a flare-up of discipline problems. Eleven West students were arrested last week following a series of fights at the school.
At the time, Wright said that those incidents were "totally unusual" and that he believed they stemmed from problems in the neighborhood.
But Joy Herbert, who has a son in 11th grade and is cochair of West Philadelphia's school advisory council, said she has visited the school twice a week and has seen students roaming the halls.
"Those classrooms are out of control," she said. "There's no sense of order or anything."
West held an "all-hands" meeting with teachers and other staff Wednesday to announce Wright's departure and Chapman's arrival. Nunery said he read aloud Wright's letter outlining his reason for taking the leave.
The letter does not reveal the health issues Wright is grappling with.
Wright could not be reached for comment.
His appointment to West this fall was the third time he was tapped to administer his alma mater.
Wright, a retired Army captain, served as West's principal in 2002-03 until his Army Reserve unit was deployed to Fort Drum, N.Y.
Former district chief executive Paul Vallas returned Wright to West as coprincipal in the spring of 2007 after the school was rocked by violence and a rash of fires.
That fall, Wright resumed his post at the helm of the district's military high school at Leeds, and Saliyah Cruz became West's principal.
During her three years at West, Cruz was credited with improving the school's climate and winning support from students and a corps of young teachers she recruited. During her tenure, West was removed from the state's list of "Persistently Dangerous" schools under the federal No Child Left Behind law.
But Superintendent Arlene Ackerman said she was not satisfied with the school's academic progress and transferred Cruz to another school. Ackerman brought in Wright and paired him with LaVerne Wiley, another veteran administrator.
Wiley, who had focused primarily on academics, was reassigned last week to a troubled elementary school.
During the 2009-10 academic year, Wright was sent to South Philadelphia High School to help bring calm after it was shaken by attacks on Asian students.
Contact staff writer Martha Woodall at 215-854-2789 or firstname.lastname@example.org.