In a season where precious little has gone right for the other broadcast networks in terms of new shows, almost everything has gone at least decently for CBS, which hasn't had to cancel any of its new shows, even though none have turned out to be a breakout hit. So it's not surprising that CBS would both be the last of the Big Four to announce a mid-season schedule, and that the mid-season schedule would be more about tweaks than wholesale changes.

The big developments:

* Starting Jan. 19, "Blue Bloods" (which has drawn a solid but old-skewing audience on Fridays) gets a four-week tryout Wednesdays at 10 to see how it does in a more high-profile timeslot, and with "Criminal Minds" as is lead-in. It moves back to Fridays at 10 on Feb. 11.

* "Blue Bloods" will be displacing "The Defenders," which has struggled the most of CBS' rookies and will relocate to Fridays at 8 starting Feb. 4. "Medium" will have aired its series finale by then.

* When the "Blue Bloods" Wednesday tryout is done, that 10 p.m. timeslot will go to "Criminal Minds: Suspect Behavior," the long-awaited spin-off starring Forest Whitaker and Janeane Garofalo. Slotting the two "NCIS" shows back-to-back has done fine for the network, so the thinking behind a "Criminal Minds" double-feature makes sense.

* "Mad Love," a sitcom about four young New Yorkers - Jason Biggs, Sarah Chalke, Tyler Labine and Judy Greer - will get the Monday at 8:30 timeslot (leading out of the compatible-sounding "How I Met Your Mother") starting Feb. 21. That move bumps "Rules of Engagement" to Thursdays at 8:30 starting three nights later, and for the time being bumps "Feces My Dad Says" off the schedule altogether.

CBS also announced that "Chaos," a light-hearted drama about a group of rogue CIA spies (including Freddy Rodriguez, Eric Close and Kurtwood Smith), will air Fridays at 8 starting April 1.