Wong, the starting second baseman to open the season, and reserve outfielder Shane Robinson were optioned to Triple-A Memphis on Monday. Rookies Greg Garcia and Randal Grichuk, both off to strong starts, were recalled from Memphis and are in the majors for the first time.
The 23-year-old Wong was batting .225 with five RBIs in 71 at-bats and didn't play in the last two games of a weekend series against Pittsburgh. Robinson was batting .100 with no RBIs in 20 at-bats.
Mark Ellis will start at second base for the Cardinals.
"This will give [Wong] a chance to play every day [at Memphis], and if he gets back on track, that would be helpful," general manager John Mozeliak told the St. Louis Post-Dispatch.
Garcia was batting .267 at Memphis with a team-leading five home runs and three triples while starting at second base. Grichuk, acquired from the Angels last offseason, was batting .310 with a team-leading 17 RBIs and 16 runs and was hitting .421 with runners in scoring position.
Information from The Associated Press was used in this report.