Last season, Parraz hit .289 with six homers and 42 RBIs for Salem in the Class A Carolina League. Prior to the season, Baseball America ranked his arm as the best in Astros' organization.
Parraz, 24, is a right-handed batter who played center field and right field last season. He stole 21 bases and drew 64 walks. A third-round Draft selection in 2004, Parraz was named Most Valuable Player at Class A Tri-City in 2006 and at Class A Lexington in 2007.
The Royals assigned him to Double-A Northwest Arkansas.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.