Brothers & Sisters is far from the least worthwhile new series of the season. But it is easily the most disappointing.

The indicators pointed to something special. The cast was stellar: Calista Flockhart in her post-Ally McBeal return to episodic TV; Rachel Griffiths, off a stalwart run on Six Feet Under; Patricia Wettig, most recently a secondary character on Prison Break but beloved by many for thirtysomething. Then it got starrier still when Sally Field became a belated hire.

The creative team included acclaimed playwright Jon Robin Baitz, actor-producer-director Ken Olin — Wettig’s real-life husband — and Marti Noxon, who ran Buffy the Vampire Slayer after Joss Whedon bailed. Another positive sign was ABC’s scheduling of Brothers & Sisters after Desperate Housewives. This stamped it as the network’s most prized newcomer.

Alas, stuff happened. The original pilot was the only one of ABC’s new series not provided to critics in advance of the summer network press tour. It would be shown at the gathering in Pasadena, writers were promised. It wasn’t. Dependable Canadian critics who got an opportunity to see it reported it was an embarrassment. Their assessments gained credibility when the producers acknowledged on the press tour that extensive reshoots were necessary.

Among the changes: Betty Buckley, who was cast as the matriarch in the family drama, was cut loose, opening the door for Field.

Everything was fine now, critics were told. Clearly they weren’t. Not long after the press tour, Noxon left the show due to "creative differences."

In spite of all the ominous portents, Brothers & Sisters isn’t that bad. It just isn’t very good, especially considering all the proven talent involved. The basic problem is the show is much too slow and talky. As a result, even a traumatic event in the final scene of the premiere, which is intended as a cliffhanger, packs no wallop. The writers have given the audience no reason to care.

This could be partially a product of having to introduce so many characters and explain their relationships. But other new series — most recently Studio 60 on the Sunset Strip — have overcome this challenge in a way that is satisfying and arresting.

Flockhart plays Kitty Walker, a conservative radio talk host — a career choice that becomes a flashpoint for the rest of her family. Kitty, based in New York, is about to return to her native blue state California after three years away. In addition to celebrating her birthday, she has scheduled an audition to take her act to TV during her time on the West Coast, but it’s not a job she really wants. She loves New York and hates the idea of living close to her judgmental family again.

Most of all, she dreads seeing her mother, Nora (Field). There’s an inexplicable but very really schism between the two. The dramatic tension in the scenes with Flockhart and Field crackle like a downed power line.

Griffiths plays Sarah, Kitty’s closest ally. Sarah is the daughter who stayed home, had a family and still manages to serve as her father’s right hand in running the family’s prosperous produce business.

One of their brothers, Tommy, is a married skirt-chaser. Another, Kevin, has just come out; neither he nor Kitty can understand the other’s politics. The baby of the family, Justin, is a rebellious, emotional wreck. The expedient rationalization is a bad reaction to his military service in Iraq. However, this might be just a handy excuse for his enthusiastic abuse of drugs and alcohol.

Balthazar Getty plays Tommy, Matthew Rhys is Kevin and Dave Annable is Justin, the only one who gets the opportunity to rise above the rest in the busy premiere. Tom Skerritt is effective as the family patriarch, William Walker, but he is not going to be a regular.

Ron Rifkin plays Nora’s brother, Uncle Saul, who handles — and secretly cooks — the books for the Walkers’ business. It might not be for personal gain, however. A mystery woman barely introduced, played by Wettig, seems to have her fingers in the family pie.

As the last show in prime time on Sunday, Brothers & Sisters does have one upside. It will make the weekend seem longer.