Starlin Castro yelled at himself and walked slowly back to the dugout, checking the replay on the video board in left field and squeezing the bat as if he wanted to break it over his knee.

Colorado Rockies closer Rafael Betancourt had just struck out Castro with three straight pitches clocked at 93 mph, leaving two men on base in the ninth inning of Thursday's 7-5 loss at Coors Field.

Castro swung and missed in the clutch, and this is where the Cubs feel Castro has to – will – get better.