WHAT IT’S ABOUT MacKenzie (Kaitlin Olson, “It’s Always Sunny in Philadelphia”) finally decides to visit her estranged sister in Greenwich, but her timing is not good. During a party, the FBI arrests both sister and billionaire husband, leaving Mackenzie, or Mickey, in charge of the kids. They’re brats, or at least teen Sabrina (Sofia Black-D’Elia) and Chip (Thomas Barbusca) are. (Their 7-year-old brother, Ben — Jack Stanton — hasn’t been corrupted yet.) They’ve also never had a baby-sitter quite like their aunt. Her boyfriend, Jimmy (Scott MacArthur), moves in to the mansion shortly, and with housekeeper Alba (Carla Jimenez), they’re one big almost-happy family.

MY SAY You’ll be disappointed to learn that “The Mick” doesn’t refer to Mickey Mantle, but relieved to know it’s not intended as an ethnic slur either. The Mick instead is Olson’s character, MacKenzie, whose name is reduced to “Mickey” and finally The Mick. The Mick drinks hard, or drinks anything (gasoline, by accident, at one point). She smokes and cusses. She pile-drives her way through supermarket aisles while product-testing, or product-destroying. That’s all established before the opening credits.

There’s some of “Sunny’s” sweet Dee Reynolds in The Mick, but possibly a touch of Kristen Wiig’s Annie, from “Bridesmaids,” too. Or maybe those are just distant echoes — blue ones — of a lot of other funny female comics, like Amy Schumer, Ilana Glazer, Jenny Slate or Sarah Silverman.

Or maybe not. But at least you start to get an idea of what The Mick could be in an ideal world, or in a better sitcom. Olson absolutely has the talent to pull this off too — again, in that ideal world/sitcom. Fearless on “Sunny,” there’s probably nothing she hasn’t done on the long-running FX hit, and it’s hard to imagine “Sunny” would’ve lasted one season, much less 11, without her.

She’s earned her solo prime-time shot. So what, then, has she done to earn “The Mick”? There are a few (astonishingly) vulgar jokes over Sunday’s opening 24 minutes — not necessarily by Fox standards (some animated shows in particular) and certainly not by “Sunny” ones. But this newcomer is about to get a huge audience lead-out from an NFL game. That’s a great way to offend a lot of people in a hurry. “Mick” would’ve been better served by a soft launch, or (better yet) a relaunch after a retool.

Vulgarity’s hardly the problem for intended viewers (14-year-old boys, or adolescent-boys-at-heart, or “Sunny” viewers). The material’s the problem. “The Mick” lumbers along instead of flies. Scenes grope for punchlines that — when or if they come — lack punch or just belly-flop. “The Mick” wants to be outrageous, but instead settles for excessive.

You’re finally just left with some potential — Olson — in search of a funny premise. After three episodes (next week, Mick teaches Sabrina the facts of life, then Ben gets a surprise at his birthday party) the search is in vain.

BOTTOM LINE Hey, at least the first vomit jokes don’t arrive for a couple of weeks.