Second baseman Steve Lombardozzi and pitchers Brad Peacock and Tom Milone will get the promotion. The Nationals have to put them on the 40-man roster, and they haven't decided who they will take off.
Lombardozzi, who is expected to be the leadoff hitter of the future, is hitting a combined .312 with eight home runs, 50 RBIs and 80 runs scored for Double-A Harrisburg and Triple-A Syracuse this season. The Nationals are planning to use Lombardozzi at second base, shortstop and third base.
Peacock is expected to be in the rotation behind right-handers Stephen Strasburg and Jordan Zimmermann in the future. He is a combined 13-3 with a 2.44 ERA for Harrisburg and Syracuse.
Milone has a 3.43 ERA and has allowed a mere 13 walks in 136 1/3 innings.
The Nationals also plan to call up players already on the 40-man roster. However, the source declined to name who will get a chance to play in the Major Leagues.