The 25-year-old faces up to 90 years in prison for the largest leak of classified government information in U.S. history.
Manning did not make a statement at his trial.
Defence attorney David Coombs said Manning will give a statement Wednesday. The defence team is set to begin presenting evidence Monday.
The former military intelligence analyst gave more than 700,000 documents and some battlefield video to the anti-secrecy website WikiLeaks while working in Iraq. He was convicted last month of 20 counts, including federal Espionage Act violations and theft.
Manning says he leaked the material to expose wrongdoing and provoke discussion about U.S. military and diplomatic affairs.
The prosecution's case has tried to show what damage the leaks may have caused.
The revelations put entire Afghan villages at risk of harm from the Taliban for co-operating with U.S. forces, a Defence Department official testified Friday.
Navy Rear Adm. Kevin Donegan, director of warfare integration, was director of operations for U.S. Central Command, including Iraq and Afghanistan, when WikiLeaks began publishing the information in 2010.
Donegan said WikiLeaks' publication of more than 90,000 Afghanistan battlefield reports in July 2010 prompted the creation of a crisis team to assess whether the documents contained anything immediately useful to the enemy or identified people who had given information to U.S. forces.
He said the team found "a significant number" of such people, who had to be warned they were at risk.
"Each area of Afghanistan has a shadow Taliban governor associated with it," Donegan said. "Villages, in and of themselves, for co-operating with the United States, can be retaliated against by the Taliban."
Donegan refused to testify in open court about the number of people who were warned. He later testified in a closed session, where he presumably provided classified details of the mission.
On cross-examination, Donegan said he was unaware of any casualties suffered by troops travelling to dangerous areas to inform people at risk.