CBS took an “if it ain’t broken, don’t fix it” approach to putting together its 2009-2010 television schedule.

Because of the ratings success the network has had the past year only a few changes were announced Wednesday, including four new shows plus one transplant from another network.
Coming to the CBS schedule in September are the new dramas “NCIS: Los Angeles,” “Three Rivers” and “The Good Wife” plus the comedy “Accidentally on Purpose.”
CBS has also picked up the Patricia Arquette series “Medium,” which was canceled by NBC after five seasons. The series will be paired with “Ghost Whisperer” on Friday nights.
Here’s a look at the new shows:
“NCIS: Los Angeles”: Chris O’Donnell and LL Cool J star in this spinoff of “NCIS.” The group looks into crimes involving the military using high-tech equipment.
“The Good Wife”: Julianna Margulies plays a wife and mother who must return to work as an attorney after her husband gets arrested.
“Three Rivers”: Alex O’Loughlin portrays the head of a transplant surgery team. This is a return to CBS for O’Loughlin, who starred in the short-lived vampire drama “Moonlight.”
“Accidentally on Purpose”: Former “Dharma & Greg” star Jenna Elfman plays a journalist who gets pregnant. The father is a much younger man.
To make way for the new shows, CBS canceled “The Eleventh Hour,” “Worst Week,” “Without a Trace,” “The Ex List,” “The Unit” and “Flashpoint.”
“The Mentalist” is moving from 9 p.m. Tuesdays to 10 p.m. Thursdays, and “The Big Bang Theory” will no longer lead off the Monday night schedule. The comedy moves to the prime 9:30 p.m. time slot between two big CBS hits, “Two and a Half Men” and “CSI: Miami.”
In case any of the new shows stumble, the network has five midseason replacements waiting in the wings. “Miami Trauma,” starring Jeremy Northam, is a medical drama and “The Bridge,” starring Aaron Douglas, is a police drama. The comedy “Rules of Engagement,” plus the reality shows “Undercover Boss” and “Arranged Marriage,” are the other potential additions to the CBS lineup.