The team also sent reserve outfielder Shane Robinson to Triple-A Memphis and brought up two rookies, infielder Greg Garcia and outfielder Randal Grichuk.
Wong, 23, is batting .225 with no home runs and five RBIs in 71 at-bats this season and sat out the final two games of last weekend's series against the Pittsburgh Pirates.
Wong, who has just four hits in his last 28 at-bats, had earned the starting job out of spring training. The Cardinals' 2011 first-round selection will return to Memphis to correct his struggles at the plate and obtain regular playing time once again.
Veteran Mark Ellis will start at second base for St. Louis.
"We can give (Wong and Robinson) some at-bats. They weren’t getting a lot of playing time here in the last couple of weeks and, especially for Wong, that trend probably would continue,” Cardinals general manager John Mozeliak told the St. Louis Post-Dispatch.JAFFE: Common sense prevails with transfer rule update