A career .297 hitter with a .336 on-base percentage when the season began, Castro has stumbled out to a .235 batting average and .269 on-base percentage over the first 70 games of the season.
The reaction from Cubs president of baseball operations Theo Epstein is that the struggles have the potential to benefit the 23-year old down the road.
"Failure is innate in baseball; it's inevitable," Epstein said Thursday on ESPN 1000's "Waddle and Silvy" show. "It's actually an important part in the development of the development process. Starlin is someone who went very quickly through the upper minor leagues. If you look at the number of at-bats he had at the Double-A and Triple-A level, there are not very many and he was in the big leagues instantly and had success."
What the Cubs hope that is happening is that Castro is now undergoing a missing piece of his development.
"Because he never failed, he never had to make adjustments as an offensive player and he's going through that now; he's struggling," Epstein said. "He's well below the high standards he has set for himself. That means it's failure, it's a slump and it's incumbent on him to work his way out of it and for us to help put him in a position where he can get out of it and I think that he will, and he will be a better player in the long run because of it."
June has been particularly rough on Castro, who has driven in just three runs during the month while carrying a .134 batting average, a .183 on-base percentage and a .194 slugging percentage.
"His ability hasn't gone away," Epstein said. "His ability to hit .300 hasn't gone away. His ability to again become a guy that drives a baseball and will grow into significant extra-base threat hasn't gone away while staying at shortstop. All that stuff is still there and it's why he's going to be a very valuable asset for a long time. It's simply masked by the fact that he's in a deep, deep slump."
The idea now is that when Castro emerges from this slump, he will be equipped with the knowledge of how to minimize struggles in the future.
"One day a bloop a single will fall in and you will start feeling natural again all of a sudden," Epstein said. "You'll start seeing the ball better. You'll start driving the baseball. We can't do that for him, but we can help work with him and eventually he will get out of it and will realize that failure is temporary in this game and you can get out of it with proper adjustments and he will be better for it. Most guys go through it in Double-A or Triple-A. He's going through it in the big leagues."