'ER,' 'CSI' SET TO SQUARE OFF.

Byline: - Valerie Kuklenski

Which to watch at 10 p.m.? CBS aims to suck some lifeblood out of NBC's ``ER'' by putting the season premiere of ``CSI: Crime Scene Investigation'' in its usual ``Without a Trace'' time slot opposite the 12th-season opener of the hospital drama. Great night for TiVo, in our book.

--``CSI: Crime Scene Investigation'' (10 p.m., CBS) George Eads, who nearly lost his job on the top-rated drama a year ago over a salary dispute and his failure to show up for work, no doubt has been sufficiently humbled by last season's finale. His character, Nick, survived being buried alive, a thrilling plot point for viewers as well as a reminder for Eads that the writer-producers giveth the role, and the writer-producers can taketh it away. The whole CSI team is back on the same work shift at the behest of Grissom (William Petersen). Tonight's episode is not for the meek; there are three murders to investigate, and the producers have indicated that the coming season's crimes will be more gruesome than before.

--``ER'' (10 p.m., NBC) Last spring we said goodbye to Dr. John Carter (Noah Wyle), who moved to Paris to join his beloved Kem (Thandie Newton). Meanwhile, Luka (Goran Visnjic) and Sam (Linda Cardellini) were out on the streets of Chicago looking for Sam's son, Alex (Oliver Davis). The boy ran away from home without insulin for his diabetes, and he was spotted just before the closing credits hitching a ride in a pickup truck driven by a guy in a baseball cap. And Dr. Pratt (Mekhi Phifer) made very brief contact with his long lost father, Charlie (Danny Glover). This season, Charlie will be in more episodes, Dr. Gallant (Sharif Atkins) is back from Iraq, and Kristen Johnson (``Third Rock From the Sun'') joins the cast as a no-nonsense nurse manager.