Kansas City Royals starting pitcher Zack Greinke (elbow) will be activated from the injured list to start on Friday against the Oakland Athletics, according to skipper Mike Matheny. Brad Keller will go on Saturday and Brady Singer will get the ball on Sunday in the series finale. Greinke is ready to return to the Royals rotation after giving up three runs while walking one and striking out eight in 12 innings over two minor league rehab starts with Triple-A Omaha. The 38-year-old right-hander...