For the most part, CBS has had a very good year. New series like 'Undercover Boss' and 'NCIS: LA' lived up to expectations and emerged as hits, and even though it's fallen off a bit lately, 'The Good Wife' is also a success.

But as the May upfront approaches, when the network has to make difficult decisions about what new shows to order and which programs to axe, it's a good time to assess what might happen. Here's our look at what's Tiffany network shows are on the brink ... and how it might play out.

1. 'Accidentally on Purpose' Despite a lot of quality pedigree behind the camera and a major star -- Jenna Elfman -- in front of it, this sitcom has struggled all season long in the ratings. And it's just not a very good comedy, straining to be funny. The last episode, when Billie finally had the baby, was the perfect way to end the show. It's not worth a renewal, especially if some of the proposed pilots like William Shatner's 'S**t My Father Says' get the greenlight.

2. 'Cold Case' This is just like last season's 'Without A Trace,' a vulnerable drama series that has been going down in the ratings. 'Cold Case' is a Jerry Bruckheimer series that's had a good run, but it's time to wrap it up. The novelty has worn off and after cost cuts this season -- including no more on location filming in Philadelphia -- it's a sign that 'Cold Case' has reached its end. Also, CBS has practically assured us that 'Hawaii Five-O' and the 'Criminal Minds' spinoff are locks for the fall. Something has to move to make room for those hours. This is one; 'Medium' could be the other.

3. 'Rules of Engagement' If you were to make an analogy to sports, 'Rules' is like a reliable back up quarterback for CBS. It's the perfect mid-season tonic for whatever sitcom is not living up to expectations on the schedule. 'Rules' probably deserves a spot to call its own, but watch for CBS to continue keeping it as the back up replacement sitcom, earmarked for the second season and not a fall pickup.

4. 'Medium' While it seemed like a good move last year for CBS to snag this supernatural drama from NBC and pair it with 'Ghost Whisperer' on Friday nights, it hasn't really panned out in the ratings. But how much of that reflects on the show or the lack of viewers on Friday nights? TVbythenumbers.com puts 'Medium' on the endangered list and that's probably a correct assessment. 'Ghost' has a better chance of surviving.

5. 'The New Adventures of Old Christine' The Wednesday night double shot of sitcoms has not worked out on CBS; neither 'Old Christine' nor 'Gary Unmarried' have offered much in the way of ratings zing. The former, at least, has critical approval and has had a good run. Last year, it was saved from cancellation by ABC offering to snatched it up if CBS let it go. That won't happen this go-round. Julia Louis-Dreyfus will be doing something else on TV in the near future.

6. 'Gary Unmarried' CBS will pull the plug on Jay Mohr's sitcom. It hasn't found a niche, and it failed when they've tried to move it into a Monday slot. There are too many new pilots in the works that have a better shot than another season of 'Gary.' For instance, there's a new Chuck Lorre sitcom waiting in the wings.

7. 'Two and a Half Men' Yes, CBS has already renewed 'Men' for two more years, but that extension has been jeopardized by the Charlie Sheen situation. If WB and CBS comes to terms with Sheen, which is likely, 'Men' will be back for the fall. It might be moved to 9:30 PM on Monday nights, but it will return. CBS has too much invested in this show's ongoing success to let Sheen bolt.