WASHINGTON -- Infielder Zach Walters is one step closer to the big leagues. On Friday morning, Walters was promoted to Triple-A Syracuse, according to a baseball source.

Before the promotion, Walters was hitting a combined .280 with 11 home runs and 43 RBIs for Class A Potomac and Double-A Harrisburg. He joined the Nationals' organization in July 2011, in a trade that sent right-hander Jason Marquis to the D-backs.

Washington has been looking for a backup middle infielder since shortstop Ian Desmond went down with an oblique injury last month. It's not known when Desmond will return to action.

If Walters were promoted to the big leagues, he would spell Danny Espinosa and Steve Lombardozzi at shortstop and second base, respectively.