The left-hander requested $925,000; the club countered with $775,000. A ruling is expected Friday.
Burnett said he was not upset about the arbitration process, but wished he had come to an agreement with the team. He declined to say what the Nationals said about him during the hearing.
"It was interesting," Burnett said by phone. "I learned a lesson. I don't want to deal with it again."
Last season, Burnett went a combined 2-3 with a 3.12 ERA for the Pirates and Nationals. He was part of the Nyjer Morgan trade that sent right-hander Joel Hanrahan and center fielder Lastings Milledge to Pittsburgh on June 30, 2009.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.