Which TV stars are coming and going?
It's the circle of TV life: Just as some prime time stars ditch the shows that helped make them famous, others return to their old small-screen stomping grounds. Will such series as ''Charmed'' and ''NYPD Blue'' survive these major cast changes? Can old faces breathe new life into aging franchises like ''ER'' and ''Spin City''? We'll take it on a case-by-case basis.
''LAW & ORDER'' If any show proves that cast turnover can be a good thing, it's NBC's legal warhorse, which has seen costars exit nearly every season yet continues to grow in the ratings. Still, the loss of Angie Harmon's ADA Abby Carmichael may be the biggest blow to ''L&O'' since Chris Noth was asked to leave the show. The actress brought a Texas-size toughness and intelligence to the part. Her replacement, Elisabeth Rohm (''Bull,'' ''Angel''), will need to distinguish herself as more than just the drama's first blond babe.
''SPIN CITY'' Michael J. Fox has been dropping big hints in the press that he plans to reappear in the season premiere of his former ABC sitcom. It's not a moment too soon. With the too-cool Charlie Sheen as star, the always shaky ''Spin'' collapsed in quality last season. Too bad Fox will probably only stick around for an episode or two -- this show just ain't the same without him.
''NYPD BLUE'' After only two and a half seasons as Detective Danny Sorenson, Rick Schroder has chosen to split to ''spend more time with his family.'' Cocreator Steven Bochco already lined up another former preteen idol, Mark-Paul Gosselaar, to join the show. But the ex-''Saved by the Bell'' boy will have to show better acting chops than he did on the WB's flop ''Hyperion Bay'' if ''Blue'' hopes to hold on in its new time slot opposite: ''Law & Order.''
''ER'' Remember Sherry Stringfield's Dr. Susan Lewis? NBC sure hopes you do, as they've signed the actress (who voluntarily left the show way back in 1996) for the hospital drama's next three seasons. With much of the original cast gone -- and Anthony Edwards headed out the door after one more year -- this could prove to be a smart move, reminding viewers why they loved ''ER'' in the first place.
''CHARMED'' Stop us if you've heard this one before: ''90210'' alum Shannen Doherty has jumped ship (or was she pushed?) from an Aaron Spelling-produced drama amid reports of on-set clashes and off-set bad behavior. Jennifer Love Hewitt turned down the chance to become the WB's newest witch, so allow us to offer this casting suggestion: Jerri Manthey, the rhymes-with-witch temptress from ''Survivor: The Australian Outback.'' Hey, if Colleen Haskell can costar with Rob Schneider in ''The Animal,'' why not?