Adam Scott in "Party Down." (Starz photo)

First, the good news: Adam Scott is joining the cast of NBC’s “Parks and Recreation.”

The bad news: That means he’ll be leaving “Party Down,” assuming Starz even renews it for a third season.

Scott is a criminally underused actor (you might have seen him in “Veronica Mars” or “Step Brothers” or HBO’s depressing “Tell Me You Love Me”) with a wonderfully dry, deadpan delivery who should fit in perfectly on “Parks and Recreation.” (In fact, with his addition, Paul Schneider’s Mark Brendanowicz suddenly looks expendable.) Scott will appear as Leslie’s love interest in the last couple of episodes this season, then become a regular next fall.

So what does that mean for “Party Down”? Nothing good. The second season of the under-the-radar comedy about caterers has already been filmed (it starts airing in April), so he’ll still be starring in that. But if there’s a third season, he’ll only be available for a maximum of three episodes, which would suck, him being the main character and all. The series faced a similar situation with Jane Lynch, who was hilarious in “Party Down’s” first season, then jumped ship to Fox’s “Glee.” She’ll be back in Season 2 for just one episode. “Party Down,” meanwhile, hasn’t been renewed yet, and Starz has a new president who might want to usher in some of his own shows, especially when the show keeps bleeding its best cast members. Well, if worse comes to worse, it’ll have had a good two-season run, and done its part to bolster other comedies.