"I love what he's doing and am enjoying it while he's doing it," Cubs manager Mike Quade said.
Soriano deserves an assist. Castro and Soriano stick to their pregame routine religiously and go to the batting cage together for sessions with hitting coach Rudy Jaramillo.
"That's the only way you can get better is working," Soriano said. "He's good, but if he doesn't work, he'll just stay good. He won't get better."
Last May 7, Castro was promoted from Double-A to the big leagues. He's still got work to do. The Cubs would still like to see more plate discipline, but not if it takes away from his effectiveness. He's batting .418. Why mess with that?
"I think he'll be even better if he can learn to lay off some of those pitches," Quade said. "Maybe he never does that and he becomes a fabulous hitter who has a large strike zone. He understands. He's pretty good [with pitches] down, especially before he gets two strikes. There's areas of discipline that he shows you, but once he gets two strikes, he does expand and it's amazing.
"He doesn't swing and miss very often. If he can reach it, he usually gets a piece of it."
Castro also has thrived at the top of the lineup. He's 18-for-32 (.563) and has scored eight runs in seven games as the leadoff man.
"I can stay in the leadoff spot," Castro said after Sunday's game, in which he had two singles, an RBI double, a walk and scored two runs. Quade gave Castro the green light on a 3-0 count in the fourth, and the kid delivered with his two-out RBI double.
"I'm working harder at being more disciplined and taking more pitches and taking a walk," Castro said. "The leadoff hitter has to score a lot. I'm seeing the ball pretty good, I'm swinging at strikes."
"I'm so proud of him," Soriano said. "He's 21 years old. What he did last year surprised me. What he's doing so far [this year] is also a surprise."
Castro has also been able to handle more interviews in English. He's working on it.
"He's a little shy with the media," Soriano said. "He likes to talk, but in English, he's a little shy."
Give him time, and Castro will figure it out.
"His talent is obvious," Quade said. "I'll be real anxious to see where he's at in a couple years."