CHICAGO ¨C The Cubs made a decision this season to let rookie center fielder Pete Crow-Armstrong continue his development in the big leagues. The ballclub knew his defense and speed were ready for the Majors, but the offensive side would require patience and experience to catch up.

¡°Day in and day out,¡± Crow-Armstrong said, ¡°we¡¯ve been working on how to get me being completely myself in the box and unlocking the good parts of me as a hitter. There¡¯s been a lot of hand-holding through that, but I¡¯ve come a long way.¡±

In a 6-3 win over the Cardinals on Friday afternoon at Wrigley Field, Crow-Armstrong turned in a performance that continued to fuel hope that he is turning a corner for the final two months. Crow-Armstrong is very much a part of Chicago¡¯s blueprint for next season and beyond and a strong finish would help boost fan optimism over his offensive trajectory.

Facing St. Louis right-hander Erick Fedde ¨C acquired from the White Sox ahead of the Trade Deadline earlier this week ¨C Crow-Armstrong connected for a hard-hit single (100.3 mph exit velocity, per Statcast) to drive in a run amid a five-run outburst in the second. In the seventh, the rookie drew a walk against reliever Shawn Armstrong and promptly stole second base.

¡°Just good at-bats,¡± Cubs manager Craig Counsell said. ¡°The walk, as much as anything, was just a fantastic at-bat. And then, he did his thing on the bases. ¡­ He¡¯s really been making better swing decisions. And when he gets balls in the zone, squaring them up really well.¡±

The overall offensive numbers have not been pretty for the 22-year-old Crow-Armstrong, but the Cubs believe the Major League growing pains will be worth it in the long run as learning moments. Through 73 games, the rookie has hit .194 with a .550 OPS and a 54 wRC+, meaning he has performed 46% below MLB average in the box.

That said, Crow-Armstrong has been elite on multiple other fronts.

Per Statcast, he ranks in the 99th percentile in sprint speed (30.1 ft/sec). He reached 29 feet per second on his seventh-inning steal, which made him 21-for-21 in stolen base attempts this year. That tied Quintin Berry (2012) for the second-most steals without being caught to to start a season for a rookie. Mitchell Page (26 in 1977) boasts the record.

¡°My baserunning knowledge has expanded a lot this year,¡± Crow-Armstrong said. ¡°It¡¯s going out there and being able to be confident and taking the next base, and wanting to move forward. Everybody¡¯s emphasized so much that that creates chances, that makes it harder on the pitcher.

¡°And if anything, selfishly, it¡¯s helped me in the box, you know? All I've got to do is get on first base, and we know we want to run and cause havoc.¡±

Defensively, Crow-Armstrong has piled up 11 Defensive Runs Saved, which is tied for the MLB lead among center fielders. Per Statcast, he is in the 96th percentile for arm strength (93.5 mph), 95th percentile for range (seven Outs Above Average) and 94th percentile in Fielding Run Value (eight).

Counsell said recently that the behind-the-scenes conversations with Crow-Armstrong have really centered around pointing to all the good happening within this developmental season.

¡°Really, you¡¯re kind of just filling Pete¡¯s cup up continually, right?¡± Counsell said. ¡°You have to take things in and use the things that work for you, and throw the things out that don¡¯t work for you. But there¡¯s certainly learning moments and learning opportunities, and you just keep making sure we capture those. And then hopefully over time, you see progress.¡±

In the second inning, Isaac Paredes led off with a 12-pitch battle that ended in a strikeout, but was surely taxing on Fedde.

Nico Hoerner followed with an opposite-field single and Dansby Swanson then legged out an infield hit, setting things up for Crow-Armstrong. The rookie pulled a 3-1 cutter into right to give the Cubs their first run. Christian Bethancourt (three-run homer) and Michael Busch (solo shot) then piled it on against Fedde in his Cardinals debut.

Both of the balls Crow-Armstrong put in play on Friday were 100-plus mph, continuing a recent trend. His average exit velocity climbed to 85.7 mph in July, following marks of 81.3 mph in June and 83.8 mph in May. Those are signs of progress that the Cubs hope to see carry through the remainder of the year.

¡°It¡¯s incremental and it¡¯s small steps,¡± Counsell said. ¡°But I think the last two weeks of at-bats have been a positive step, the consistency of just getting to hard contact more often.¡±