Cox, the 25th overall pick in the 2010 Draft, went 2-for-3 with an RBI and reached base four times in his Double-A debut as the Springfield Cardinals stomped the visiting Corpus Christi Hooks, 12-6.
The 21-year-old third baseman played four games for the Rookie-level Gulf Coast League Cardinals last year before heading to the elite Arizona Fall League, where he hit .333 with two homers and 14 RBIs in 18 games.
Starting the 2011 campaign with Palm Beach in the Class A Advanced Florida State League, Cox batted .335 with three homers and 20 RBIs in 42 games before getting the call to the Texas League.
"There's nothing but great things to say about him," Cardinals field coordinator Mark DeJohn told the Springfield News-Leader. "Nobody, and I mean nobody, will outwork this kid. He's got a great attitude. Now it's just a matter of finding out how much ability he has."
It didn't take long for Cox and the Cardinals to make their mark Wednesday. Seven of their first eight batters collected hits, including Cox's RBI single, as Springfield scored six times to chase Hooks starter Kyle Greenwalt.
The Hooks bounced back with two runs apiece in the second and third, but the Cardinals answered with three in the fourth and three more in the fifth to put the game out of reach.
While Cox impressed in his Double-A debut, he had a lot of company as the Cardinals pounded out a season-high 18 hits and matched their highest run total of the year.
Matthew Adams continued his remarkable three-game tear by going 5-for-6 with a two-run homer and three runs scored. The Slippery Rock University product is 11-for-17 with three longballs and six RBIs in his last three contests.
Steven Hill fell a triple shy of the cycle, going 3-for-6 with a solo shot, a double and a pair of RBIs, while Alex Castellanos added a two-run blast, his 11th, and two singles.
Springfield starter David Kopp (1-2) notched his first win of the season, despite yielding four runs -- two earned -- on six hits and four walks over 5 2/3 frames. The right-hander induced 11 groundouts, two flyouts and struck out a pair.
Greenwalt fell to 2-5 after allowing six runs on seven hits and a walk while retiring one batter -- on a strikeout. It was his shortest outing since his pro debut, when he surrendered six runs and recorded one out for the Rookie-level Greeneville on July 11, 2007.