Castro committed three errors in one inning, which led to three unearned runs, on Monday against the Rockies
"He knows he didn't have a real good night, and we know he's not going to have a lot of nights like that," Cubs manager Mike Quade said. "We all make mistakes. They got bunched up and that's tough, but he'll be fine. I'm not an excuse maker, but it wasn't a great night to play."
Both teams had to deal with rain, wind and cold at Wrigley Field. The Rockies were outhit, 11-4, but won the game, 5-3.
DeJesus told Castro he needs to be better prepared.
"I think he was a little late [on a couple of the plays]," DeJesus said. "Sometimes on wet grass, you have to slow things down. He's learning every day."
Castro was back in the leadoff spot on Tuesday, where he'd hit .500 (23-for-46). He's now 2-for-17 in the No. 3 hole. Quade said he hasn't noticed a change in Castro's approach.
"Look, we think this guy is a pretty important part of our future," Quade said of the 21-year-old shortstop, the youngest player in the Major Leagues. "I have no concerns about his psyche no matter where he hits. If he showed up tomorrow and was hitting fourth, I don't think he'd blink.
"We're looking for a three-hole hitter and we're looking for one for [the long term]," Quade said. "I want to find out. He's going to lead off today, and we'll go back and forth with left-handers and right-handers in our lineup [against Rockies left-hander Jorge De La Rosa].
"He's talented and capable and going through the first month of our season. He's our best hitter and that's supposed to be your third guy. We'll see how it plays out."
Castro has shown he can hit. He also needs to show he can handle shortstop. Both starting pitcher Matt Garza and second baseman Darwin Barney shouldered blame for Monday's loss, deflecting some of the focus off Castro. Quade liked hearing that. It doesn't mean Castro shouldn't learn from his mistakes.
"He has to play defense every day," DeJesus said.