His lawyer says the prosecution and defense have not agreed to a stipulation of facts in the case, which is an indication that they did not reach a deal to limit his punishment.
Bergdahl is charged with endangering his comrades by walking away from a remote post in Afghanistan in 2009.
He told the judge that he now understands that what he did caused others to search for him.
President Donald Trump has called Bergdahl a "no-good traitor" who "should have been executed."
Bergdahl began telling his story publicly for the first time in December 2015 on the second season of the popular "Serial" podcast.
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