According to Gene Duffey, an MLB.com contributor, Chapman had a bullpen session in the morning and impressed scouts with his velocity. Rizzo was not available for comment.
Chapman, 21, became a free agent after he defected from the Cuban National Team on July 3.
Whether the Nationals can sign Chapman remains to be seen. Rizzo said early this month that the Nationals most likely would not break the bank when it came to signing big-name free agents.
Bill Ladson is a reporter for MLB.com This story was not subject to the approval of Major League Baseball or its clubs.