Angels right-hander Dan Haren cut short a throwing session in the bullpen Wednesday after feeling discomfort in his lower back. “The lower back kind of tightened up,” Haren said after the Angels’ loss to the Royals. “It was in the middle of my pitching motion. I went down, I think to my knees. It came out of nowhere. It hurt enough for me to go down. “ Haren is scheduled to start Saturday against the Yankees, but manager Mike Scioscia said he’s not sure whether that will happen.