LaRoche, 24, had two pins inserted to reattach the ligament in a procedure performed by Dr. Steve Shin in Los Angeles. The pins will be removed after three weeks, after which he will begin a rehab program expected to last another five weeks.
LaRoche was injured on a freak play Friday when a pickoff throw from catcher Danny Ardoin ricocheted off a baserunner and struck LaRoche at the base of his thumb.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.