Fall TV preview: Thursday's returning shows

DIAGNOSIS MURDER
CBS 8-9 PM Starts Sept. 23

Good news for everyone who was worried Diagnosis Murder was getting a lit-tle too gritty and edgy. ''We're toning down any violence,'' says the 73-year-old star, Dick Van Dyke. ''We found that there's a pretty good-size audience out there that doesn't want to see sex and violence.''

Maybe we haven't been watching closely enough (in fact, we know we haven't), but since when did DM start kickin' it Oz-style? No matter. It's nice to know the six-year-old CBS staple will steer clear of beheadings and bare butts. After all, this show — which follows the adventures of mystery-solving physician Mark Sloan (Van Dyke) — is the lone heir to the Murder, She Wrote mantle of breezy, family-friendly homicide. A greedy couple kills the bride's rich father at a wedding? Dr. Sloan figures it out in 50 minutes. Sure, we may not commit to Murder every week, but it's good to have it around — sort of like your grandmother in Florida.

As TV vet Van Dyke points out, ''In today's terms, we are not hip. But I think some of the shows have gone so far through hip they've come out the other side, and they're square again. We're liable, just by default, to become hip again.'' Exactly.

Here's what else is happening with CBS' default hipster show: It now airs in the apropos 8 p.m. time slot (which pits it against Friends); it'll get a new cast member, Joanna Cassidy (Don't Tell Mom the Babysitter's Dead), playing a hospital administrator who embarks on a Moonlighting-style flirtation with Dr. Sloan; and it gets an alarming influx of Van Dykes. In addition to writer-costar/DVD's son Barry, brother Jerry will make an appearance as a crazed hypochondriac, and 20-year-old grandson Shane will pop up as a new medical student. ''He looks a little bit like Brad Pitt,'' says proud pop Barry.

And then there's new executive producer Chris Abbott (late of UPN's Legacy), who promises to rein in the wackiness that somehow crept into the show — in the last two seasons, everyone from aliens to Kathie Lee Gifford has appeared on Murder. ''We went in a couple different wild directions,'' sighs Barry.

Abbott will concentrate on keeping the show's cheerfully gentle retro quality intact. As she says, ''I saw a review of some show recently, and it said it had 'a wonderful dark quality.' And I said, why is dark wonderful? Why do you never see 'It has a wonderful light quality'?'' Okay, here goes: Diagnosis Murder has a wonderful light quality. — A.J. JACOBS

FRIENDS
NBC, 8-8:30 p.m.

The question on everyone's lips: After their surprise Vegas wedding, will Ross (David Schwimmer) and Rachel (Jennifer Aniston) stay married? ''All I can say is we'll deal with it in the first four episodes,'' demurs cocreator Marta Kauffman. Meanwhile, the sextet plays musical roomies: Chandler (Matthew Perry) moves in with Monica (Courteney Cox), and Rachel lives with Ross, then Phoebe, then Joey ''until she finds a home.'' Doesn't sound like marital bliss to us. (Sept. 23)