Two of those players will be right-handers Stephen Strasburg and Drew Storen, their first-round picks in the 2009 First-Year Player Draft.
Strasburg will start in the Instructional League starting in October before playing for the Desert Dogs. The Nationals are hoping that Strasburg will pitch a combined 35-50 innings in both leagues.
"Strasburg will probably get to pitch maybe 20 innings in the Instructional League to ramp him up [for the AFL]," general manager Mike Rizzo said.
Storen has been excellent since he signed his first professional contract in June, going a combined 1-1 with a 2.20 ERA and eight saves at three Minor League stops. Rizzo has already announced that Storen will not be promoted to the big leagues next month.
The Nationals also have decided that catcher Derek Norris, shortstop Danny Espinosa and first baseman Chris Marrero will play in the AFL. Rizzo said Washington has not decided who the sixth and final player will be to participate in the AFL.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.