Castro entered Wednesday's game batting .326 in September but .284 overall.
"I think about finishing strong," the Cubs shortstop said. "There are eight games left, and I just want to finish strong and be close like last year. Last year, I hit .307. I'll feel good if I hit .295 this year."
There are other numbers which Castro has improved upon. He has set personal highs in triples (12), home runs (14) and RBIs (77).
"I have more homers than last year, more RBIs than last year, more triples than last year," Castro said. "That's what I'm looking for. I want to finish hard. I want to show I can be close to a .300 hitter every year."
Castro doesn't have to hit .300 to impress Cubs manager Dale Sveum.
"If you're .280 to .310, you'll still be in the upper echelons of all baseball," Sveum said.