(CNN) -- Army Sgt. Bowe Bergdahl has finished undergoing therapy and counseling at an Army hospital in San Antonio and could return to active duty as early as Monday, a defense official tells CNN.
Bergdahl was held captive by militants for five years before he was released in May in exchange for five Taliban members held by the U.S. military.
Some critics of the swap have said Bergdahl was a deserter who endangered colleagues searching for him.
Bergdahl went missing on June 30, 2009, in Afghanistan's Paktika province, where he was deployed with the 1st Battalion, 501st Infantry Regiment, 4th Brigade Combat Team, 25th Infantry Division.
An Army fact-finding investigation conducted in the months after his disappearance concluded he left his outpost deliberately and of his own free will, according to an official who was briefed on the report.
But there was no definitive conclusion Bergdahl was a deserter because that would require knowing his intent -- something officials couldn't learn without talking to him, a U.S. military official has said.
The chairman of the Senate Armed Services Committee, Sen. Carl Levin, said each of the Joint Chiefs of Staff supported Bergdahl's repatriation.
"Each of these military leaders emphasized a simple principle -- America does not leave its troops behind," Levin said. "The unanimous support of the Joint Chiefs for securing Sgt. Bergdahl's release is a powerful statement on the importance of that commitment."
Maj. Gen. Kenneth Dahl is leading the Army's formal Bergdahl investigation, which will review previous findings.
The two-star general could ask to re-interview anyone who can shed light on the case.
Talking to Bergdahl himself would likely be the last step in the investigation, one official said.
Officials say Sgt. Bowe Bergdahl has finished his therapy and counseling and will return to the Army. His disappearance while serving in Afghanistan is still under investigation.