SAN FRANCISCO -- The Cardinals on Friday placed shortstop Khalil Greene on the 15-day disabled list with social anxiety disorder, replacing him on the active roster by bringing outfielder Ryan Ludwick back from the 15-day DL.
Greene, a 29-year-old former first-round pick in the annual First-Year Player Draft who was acquired in a trade with the Padres over the winter, is batting .200 with two homers and 14 RBIs.
He's the second player in the Majors placed on the DL with an anxiety disorder this season; Tigers left-hander Dontrelle Willis missed six weeks before recently returning to Detroit's active roster.
"This is not a stress-free business," Cardinals manager Tony La Russa said before the opener of a three-game series against the host Giants at AT&T Park.
La Russa did not want to speculate as to how long Greene might be shelved.
"This is different from a physical injury, so I don't really want to go into it," said the skipper. "How I understand it, he's put a lot of pressure on himself."
Luwick, who missed 14 games with a strained right hamstring, entered the San Francisco series batting .274 with eight home runs and 26 RBIs. He was in St. Louis' starting lineup Friday, playing right field and batting in the cleanup spot.
Mychael Urban is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.