Unless they settle a dispute that dates back to Aug. 16, 2010 when Bryce Harper signed his original draft contract, the Washington Nationals and Harper will battle in a grievance hearing in December, according to sources.

The issue is whether Harper is allowed to opt out of his deal and enter baseball's arbitration system, enabling him to start negotiating higher salaries.

Harper is under Washington's control for four more seasons.

The 22-year-old is entering the final year of his original five-year, $9.9 million major-league contract. His salary will be $1 million, and he stands to earn an additional $500,000 in roster bonuses.

As a "Super Two" arbitration player — Harper has built enough service time to qualify for an extra year under the process — he would stand to earn considerably more.