With the exception of “Love Letters” and its revolving door of big-name actors, A.R. Gurney has never relied too heavily on casting stars. In some three dozen finely etched plays written over a quarter century, the inhabitants of his chosen world — the teetering demi-aristocracy of Northeastern WASPs — have long resigned themselves to the fact that their brighter, glitzier days lie irretrievably in the past. Star wattage would only blot out the diminishing surroundings even further.

This philosophy flies in the face of current theater economics, where nearly all Broadway and even many off-Broadway dramas have come to depend on the presence of at least one marquee name to justify the considerable investments. And while Mr. Gurney has largely steered clear of this system, he is not unaware of its benefits and its power inequities. “Buffalo Gal,” his latest dissection of smaller- and smaller-town WASPdom, takes a genial if ultimately superficial look at how the theatrical ecosystem can be disrupted by introducing a member of the fragile and yet ubiquitous species known as Homo celebritus.

The specimen in question here is Amanda (Susan Sullivan, herself a longtime TV fixture), whose Hollywood track record includes three Emmys, three husbands, two Oscar nominations, an estranged daughter, a history of alcoholism, and a dwindling set of career options. Amanda’s recent highlights include an episode of “CSI: Miami,” in which she played a judge with Alzheimer’s disease — “everybody does judges when they need money,” she explains — and she’s currently in negotiations to play Granny Sweetpants on a new Fox sitcom. Faced with these sorts of roles, Amanda decamps to her hometown of Buffalo to play the deluded aristocrat Madame Ranevskaya in a regional production of “The Cherry Orchard.”

That’s the plan, at least, and the crew is abuzz with nerves. It’s the day before rehearsals begin, with backdrops and old props strewn all over the stage (Andrew Jackness designed the suitably cluttered set), and Amanda has arrived a day early to calm her nerves. For all of her grandiose bows and her assurances about process and integrity, it is already clear that memorization will be an issue. This deficit is not lost on Amanda’s director, Jackie (the wry Jennifer Regan), nor is the fact that Amanda’s agent has yet to return a signed contract. And the role of Ranevskaya’s brother has abruptly been recast with an African-American named James Johnson (Dathan Williams), which rattles her more than she’d care to admit. And “the suits” would like to discuss Granny Sweetpants some more — in Los Angeles.

Mr. Gurney and his director, Mark Lamos, take their time letting the disparity in clout and commitment play out among Amanda and her co-workers. Jackie, herself an L.A. transplant, is particularly savvy at interpreting Amanda’s cues; she wants assurances that her leading lady will play well with others, but she also wants to use Amanda’s star power to secure herself some job security. James is excited to perform alongside a glamorous celebrity, but he also resents having to meet with her before rehearsals, essentially re-auditioning for a part he’d already gotten. (James Waterston and Carmen Herlihy play, respectively, jaded and wide-eyed members of the stage crew.)

Like both Amanda and her Chekhovian counterpart, however, Mr. Gurney has a hard time maintaining focus. A life-imitating-art subplot about the imminent sale of Amanda’s grandmother’s home never gets any traction, the appearance of an old suitor (a one-note Mark Blum) has a tacked-on feel, and too many of Amanda’s childhood memories feel like rehashes of sequences from stronger Gurney plays such as “Indian Blood” and “Ancestral Voices.” And while Ms. Sullivan captures Amanda’s toxic cocktail of neediness and hauteur, Mr. Lamos has her swan about a bit too much — perhaps in an attempt to hide the fact that Amanda, for all her glamour and potential for havoc, is not that dynamic a character.

In general, Mr. Gurney’s lack of interest in the disfiguring world of celebrity has been a tonic for fans of small-bore, intelligently realized theater. Chekhov is Chekhov and Granny Sweetpants is Granny Sweetpants, he seems to feel, and only under extremely tenuous circumstances shall the twain meet. When this apathy carries over into a play explicitly about that world, that’s another matter.

Until September 13 (59 E. 59th St., between Park and Madison avenues, 212-279-4200).