"I certainly hope the next two months are good for him so we can use that as a springboard into next year because this guy is a huge part of our core, a huge part of our future," Hoyer said on "The Waddle & Silvy Show" on ESPN Chicago 1000. "He's having a down year so we need to get him back to the trajectory he was on as a 21-year-old. I still see a guy who can have a lot of power as a shortstop, can hit for average. I think when he's really focused he can be a good defender. The problem is sometimes that kind of comes and goes."
The 23-year-old Castro is having the worst season of his four-year career. A two-time All-Star who led the National League in hits with 207 as a 21-year-old in 2011, Castro is batting just .248 this season with a .285 on-base percentage going into Thursday's game against the Los Angeles Dodgers.
"He's had a rough year. He's certainly been better over the last month or so but it's still not where I think we expect him to be," Hoyer said. "He's still struggling with parts of his game. The trajectory sort of hasn't been on the same ascent that it looked like it was going to be after his 21-year-old season. I think we've got to get him back to that point.
"Some of it is mechanical, I think some of it is probably confidence. As he struggled it kind of shakes his confidence a little bit. I think people have to understand, this guy has never really struggled before. When you come up to the big leagues and you're a top prospect and you get 200 hits your first full year in the big leagues ... I don't think he ever really struggled, even in the minor leagues so this is the first time he's dealt with adversity. I think he's probably learning a lot about himself."
Castro has shown improvement of late, batting .292 in July, his best month of the season.
The Cubs invested long-term contracts in Castro and fellow 23-year-old Anthony Rizzo, believing they are cornerstones of a rebuild. Rizzo has struggled at times as well in his first full major league season, batting .242 with 15 home runs and 60 RBIs.
"I think with Rizzo is working the strike zone very well," Hoyer said. "I think he's got (52) walks already this year. His power is there, you look at his doubles number (31). He's getting extra-base hits. I think he gets a little bit pull-happy at times, a lot of ground balls to second base. But I think with Rizzo, I think he will have a good two months and with him he's going to be a guy that can hit in the middle of the lineup. He's got power to all fields. I certainly hope he finishes strong but I think there's a lot of aspects of the season that have been positive for him too."