adam baldwin nathan fillion firefly 2005 gi Adam Baldwin coming to 'Castle'; Can we get Summer Glau? Alan Tudyk? Morena Baccarin?ABC’s “Castle” has made reference to star Nathan Fillion‘s “Firefly” past before. Remember that brown-coated costume Richard Castle tried on for 2009’s Halloween episode?

So it’s no surprise that TV Guide is reporting the show will stage a mini-reunion of sorts when Fillion’s “Firefly” co-star, Adam Baldwin, guest stars in an episode later this spring. Although it is a bit shocking that it’s taken this long.

Baldwin will play Ethan Slaughter “a rough and tumble cop from the city’s gang unit who lands a case that Castle is desperate to follow. Along the way, Slaughter shows Castle a dirtier side of police work that forces Castle to reconsider what he’s willing to do to close a case.”

Call us greedy but why stop at just one “Firefly” alum? Several cast members have current or recent relationships with ABC that should make it a piece of cake for them to swing some “Castle” time. Summer Glau could stop by from “Grey’s Anatomy” and Alan Tudyk from “Suburgatory.” “V” is no more but surely Morena Baccarin can rearrange her “Homeland” schedule.

Right? Right.