"I feel real good, I feel real comfortable," said Castro, who was batting .350 after Sunday's 5-4 win over the Rangers. "I feel like I have less pressure than before because I'm playing every day."
He's definitely made an impression on other teams. On Saturday, the Rangers decided they'd rather face veteran Derrek Lee with the bases loaded than Castro, so they intentionally walked the rookie with one out in the 10th inning.
"It surprised me," Castro said. "Derrek Lee has been a good hitter all his career. It was a surprise they walked me."
"He's a Major League shortstop," Cubs manager Lou Piniella said of Castro. "I enjoy watching the kid play. I even like it when he makes an out and shows a little emotion. I like that. At shortstop, he's making the plays and he's getting the throws over there with something on it."
Castro has shown his frustration when he doesn't come through at the plate. On Saturday, he was visibly upset after striking out in the eighth with a runner on.
"I want to do the job, I want to get that RBI," Castro said. "I didn't do it. I feel bad."
Told that Piniella liked seeing that kind of emotion, Castro smiled. What's more impressive is that in his 16 games so far, Castro has reached base via a hit, walk or error, and has hit safely in 14 of those.
According to Baseball Reference, the longest streak by a player to start his career since 1952 is 47 games, set by Alvin Davis in 1984 with Seattle. Castro is tied for 15th with three others, including current White Sox outfielder Juan Pierre.
"Every game, he's getting looser and looser and more comfortable," said Cubs pitcher Carlos Silva, who benefited from Castro's glovework Sunday, improving to 6-0. "That kid can play, he can hit, he can play good shortstop. The most important thing for him is he's learning. He's going to be a great player."
On the road trip, Castro went 7-for-20, including his second home run on Saturday in the third. He's fit well into the second spot in the Cubs' lineup, and the team is 6-0 when Castro starts there. Piniella hinted after Sunday's game that he may leave the rookie there against right-handers, too.
"That's where I feel most comfortable," Castro said.
Ever since his three-error game in his Wrigley Field debut May 10, Castro has shown improvement on the field and been smooth at shortstop. Give credit to coaches Alan Trammell and Ivan DeJesus. They give Castro scouting reports and also plenty of advice.
"It's a combination of everything," said DeJesus, who also is Castro's interpreter.
However, the shortstop may not need DeJesus much longer. His English has improved considerably since the season began. Castro is trying.
"He's coachable and that's a good sign," DeJesus said.
Castro has made an impact since his callup May 7.
"He brings a lot of energy to the team because he's very young," Alfonso Soriano said. "He plays great defense and he's a great hitter, too. He doesn't know what he brings to this team because he's so young, and he just wants to play baseball.
"He's 20 years old, but he doesn't act like he's 20 years old. He's a grown man."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.