WITH GREY'S ANATOMY moving to the choppier waters of Thursday at 9, it's no surprise that CBS would try to capitalize on the opportunity. Since NBC is committed to Sunday Night Football in fourth quarter—sending Law & Order: Criminal Intent to Friday and Crossing Jordan to the benches—CBS shifts Without A Trace to 10, replacing the Sunday Night Movie. Meanwhile, ABC hopes to keep the time period warm with Brothers & Sisters, an ensemble drama about a family of adult siblings who must cope with the death of their father. Although no one expects Brothers & Sisters to match the numbers of Grey's Anatomy, leading out of Desperate Housewives certainly won't hurt. But will it be enough to top Without A Trace? Chances are, it won't. At one time a comfortable second behind NBC's ER, Without a Trace now owns Thursday at 10, with an average 18.7 million viewers this season. Comparably, that's 6.4 million more than ER. Although the initial success of Without A Trace was dependent on blockbuster lead-in CSI, the show, four years in, should be able to stand on its own. And by shifting the compatible Cold Case to the lead-in 9 p.m. slot, there is no reason to believe that Without A Trace will squander the opportunity.