Last week, Castro, 21, led the Majors with 17 hits, 10 runs scored and 25 total bases. He added a .758 slugging percentage, clubbed two homers, drove in seven runs and hit safely in all seven games.
"I've been working with Rudy [Jaramillo, hitting coach] on my approach," Castro said. "Right now, I feel real comfortable."
Quade said the young infielder has shown improvement in his base-stealing abilities and knowing when to pick his spots, his defensive play, and his power.
"It should get better," Quade said. "He's a young kid. The consistency he's shown to me in all those areas in the last few months has been great."
Castro, who also picked up the honor in the first week of the season, just keeps working.
"I try to separate the two, hitting and defense," he said. "Sometimes you are playing and you hit and you're thinking too much in the field and make an error. Now, I can separate them."
In the Cubs' 1-0 win over Pittsburgh on Wednesday, Castro notched his third consecutive three-hit game and hit the game-winning homer in the eighth. The following day, he singled and scored the tying run in that same inning of an eventual 7-6 victory. On Saturday, Castro had four RBIs in the Cubs' 11-4 romp over the Reds -- his most since driving in six against those same Reds during his Major League debut on May 7, 2010.
Castro heads into this week batting .314 while leading the NL with 150 hits. That's a goal for the season, he said.
"I have to keep going," Castro said.
Quade was going to give Castro a day off Sunday, then decided not to. Castro went 2-for-5 with an RBI. He's on pace to finish with 211 hits.
"I'm just trying to finish [strong]," Castro said. "I'm not tired. I've never told Quade I'm tired, or to give me a day off. I don't need one."
Not at this rate.