"I have good talent to be a good shortstop," Castro said. "I don't want to be no joke anymore. I'm going to try to make every play aggressive. If it happens, it happens."
Maddon has stressed to the players, including Castro, the importance of defense. Castro was the subject of ridicule in August 2011 when a national television audience saw him not paying attention during an at-bat. So far this season, he's taken Maddon's words to heart.
"[Maddon] says the most impressive thing for him is, 'Next year in front of home plate, they give you a Gold Glove [Award],'" Castro said. "It's really important to me, too."
Arrieta, who picked up the win Monday, could tell Castro was playing inspired baseball.
"I saw something out of him tonight that I hadn't seen in a while," Arrieta said. "He seemed to have more of an aggressive nature about him. He was fluid. He was just tremendous at short. He stood out to me on the defensive side."
Said Maddon: "I don't know if you've seen him play better shortstop."
Castro has made one error in 12 games this season, and he has a .983 fielding percentage.
"I try to be aggressive, try to get my confidence, try to get every ball," he said. "I'm feeling really good at the plate. I'm feeling really good on defense, and that's the most important thing."
What's been the difference? Castro says it's Maddon, who is his fifth manager with the Cubs.
"I don't think about anything, just go there and play," Castro said. "The confidence they give us, that's most important."