Actors change jobs all the time, and it’s hard not to compare their work in one role to the next. TV, though, usually offers a bit of distance in between for people who are series regulars. But one of the quirks of the new TV economy, where most shows make fewer episodes per season and actors therefore have bigger holes in their schedules, is that someone might wind up with cast regular jobs on two shows airing at the same time. Already this year, we had Rob Lowe as a narcissistic actor in The Grinder (RIP) and a cynical priest in You, Me and the Apocalypse, plus Abigail Spencer and Clayne Crawford going more high-concept in, respectively, Timeless and Lethal Weapon even as the final season of their work on Rectify was running.

Now, in those instances, comparisons could only go so far, because the actors were playing such different kinds of roles, in such different kinds of shows. At one point on Rectify, Spencer’s bitter grocery store manager gets high while sitting in a satellite dish, but no one would ever think to confuse that for her time-traveling work over on NBC. You can prefer one style of performance, and show, to the other, but it’s hard to judge Crawford’s work on the two shows against each other, since one involves him jumping out a high window to shoot at a bomb, while the only thing he ever shot at on Rectify was the inflatable dancing man in front of his tire store.

With the double-feature Kaitlin Olson is about to have, though, comparisons will not only be inevitable, but unfortunate. Sunday night at 8, Fox premieres her new sitcom The Mick (its regular timeslot will be Tuesdays at 8:30), where she plays an abrasive, hard-drinking woman with little idea of how to navigate the real world — a description that applies pretty neatly to her other job as Sweet Dee on FXX’s It’s Always Sunny in Philadelphia, which returns for its twelfth season (12!) next Wednesday at 10.

Sweet Dee and Mackenzie (aka Mickey) aren’t identical — Dee came from money but has happily plunged to the gutter with her brother and his friends, where Mickey is poor but has a sister who married a rich husband, with Mickey winding up as guardian of their kids when sis and brother-in-law flee the country to evade federal fraud prosecution — but they’re close enough, and call on Olson to display so much of the same skill set from Always Sunny, that it’s not hard to imagine The Mick creators John and Dave Chernin — both former Always Sunny writers — conceiving Mickey as “a Kaitlin Olson type” and landing the genuine article. (Olson’s also a co-executive producer.)

We’re introduced to Mick in full trainwreck mode, going way past a supermarket’s free sample policy as she preps to see the estranged sister whom, as she laments, married a millionaire while Mick is dating a guy (Scott MacArthur as Jimmy) who keeps gasoline in a jar. Somehow, though, she’s not the biggest embarrassment at her sister’s party, which is raided by the FBI, leaving her in semi-permanent charge of snotty teenager Sabrina (Sofia Black-D’Elia), smug rich boy Chip (Thomas Barbusca), and little Ben (Jack Stanton), who’s too young to have been spoiled by his parents and their fortune. The kids were already being raised by housekeeper Alba (Carla Jimenez), so all the Mick seemingly has to do is raid the liquor cabinet and her in-laws’ wardrobe and make sure nobody dies.

After a decade-plus as Sweet Dee, Olson’s an old hand at playing this kind of unapologetic disaster, and for all the physical comedy required, including a botched banister slide that Fox has put in all the show’s promos. She’s more than ready for a solo showcase, especially if the schedules allow her to do both jobs at the same time.

There’s a workable, funny version of this idea that embraces the awfulness of both Mick and the older kids as they go back and forth trying to take advantage of each other in a situation lacking a functional adult — basically, an Always Sunny spin-off with the same black comic tone, only Sweet Dee is surrounded by actual children rather than the emotional kind.

But The Mick (I’ve seen three episodes) too often seems unwilling or unable to go as far and as cruel as it needs to, always pulling back just a little bit to offer evidence that, for all the insults and pranks and nastiness Mick heaps on the kids, and vice versa, they all really need each other. It’s not quite to the level of those episode-ending Modern Family voiceovers, but no story, or joke, goes as far as it needs to in order to really extract the necessary laughs. The FX version of this could be a scream; the Fox version feels watered down and largely forgettable. If anything, the half-measures make the moments where Mickey does something truly terrible, like drugging Alba without her consent, feel much worse than if the show were always being done in that key.