ST. LOUIS -- In the midst of a frustrating week, the Cardinals got some encouraging news on Monday.

Shortstop Khalil Greene will begin a Minor League rehabilitation assignment on Monday night, traveling to Memphis to begin playing with the club's Triple-A affiliate there. Greene has been on the 15-day disabled list since May 28 due to social anxiety disorder.

Acquired over the winter from the Padres, Greene struggled early in the year, and his troubles on the field exacerbated his medical situation. The club placed him on the DL in order to allow him to pursue treatment for the condition.

A non-pitching player may spend up to 20 days on a Minor League rehab assignment, and it's unclear how long the Cardinals expect Greene to be at Memphis. In his absence, Brendan Ryan and rookie Tyler Greene have acquitted themselves well both at the plate and defensively.

Khalil Greene, 29, is batting .200 with a .287 on-base percentage and a .295 slugging percentage in 38 games for St. Louis this year.