Cubs shortstop Starlin Castro struggled in the field again on Sunday, but the team has no plans to change his position. Castro already leads Major League Baseball with 16 errors. The young shortstop experienced the wrath of manager Mike Quade, who gave him an earful after Castro deflected a grounder in the first inning on Sunday with a diving play but then watched center fielder Reed Johnson chase down the ball as both base-runners moved up a bag. "It won't happen again. It better not happen again," Quade said. "He gets frustrated. He wants to make the play, doesn't make the play and just has a letdown. I'm sorry he didn't make the play. It would have been a great play. But stay involved. That bothered me." The Cubs believe Castro has improved this season. "He just needs to cut back on some of the errors on the routine plays, which certainly don't come from lack of ability to play the position," Cubs general manager Jim Hendry said. "He makes 30, 35 plays a year that we probably haven't had made before. "When people say he has to move off of short, they're just looking at the error column and thinking that he's not capable of doing it. Over time, he'll learn to cut back 10, 12, 15 errors a year just by experience."