Struggling first baseman Lance Berkman, who has had only a handful of plate appearances since coming off the disabled list, has returned to Houston to have a check of his troublesome right knee, which was operated on by a Houston doctor in May. Berkman left the clubhouse shortly after Sunday's game but Cardinals general manager John Mozeliak said, "Before we make the determination to keep pushing him or not play him, we thought it would make more sense to have a medical evaluation."