Here's Why Zack Addy Left Bones

It's been said many times before, but it bears repeating, especially for easily triggered hardcore fans: To keep a long-running series fresh for writers, cast members, and viewers, producers/showrunners need to shake things up, and this occasionally means writing out a popular character. Sometimes, they've no choice in the matter. McLean Stevenson and Wayne Rogers both left "M*A*S*H" after its fourth season because they felt they'd outgrown their characters (the former wrongly believed he was on the cusp of television stardom). Shelley Long bolted "Cheers" after the hit sitcom's fifth season to launch a semi-successful movie career.

And sometimes it's just good storytelling to take a beloved character in a wholly unexpected direction, which is exactly what Hart Hanson and the "Bones" creative team did with the Jeffersonian Institute's oddly endearing uber-nerd Zack Addy, played by Eric Millegan during the series' third season. Obviously, this was still fairly early in the show's 12-season run, but with solid ratings and a growing fanbase, it seemed highly likely that "Bones" was going to hang around for a while.

So Hanson, rather than rest on his Nielsen laurels, opted to throw one heck of a curveball by turning the likable young scientist into the protege of a cannibalistic serial killer.

The Gormogon is definitely one of the most memorably nasty villains in "Bones" history (though definitely not one of co-star David Boreanaz's favorites), so it hit as quite a shock when the writers revealed that Addy was wholly in the killer's thrall. Millegan was as stunned as anyone. As he told TV Guide in 2008:

"They met with me and told me and I was like, 'What? Zack eats people?' And they told me that I don't eat people, I kill them — I never reached the eating stage. And I was like, 'Oh, my god.' But I was kind of excited because I knew it was going to be an exciting send-off."

Exciting for the show, yes, but Millegan was hardly a star when he departed "Bones." He had a career to worry about. Though he'd be gone from "Bones" for a while, Hanson left the door open for a return somewhere down the line.

"[T]hey said, 'You know, you're not going to get killed, so we'll still have the option of bringing you back.' It was shocking, and I just had to follow it and know that this is what's happening. Zack ends up carted away to a psychiatric facility, but there is the possibility that the others may come visit me."

Millegan, who was diagnosed with bipolar disorder in 2006 (which, though a struggle, is being successfully treated and had nothing to do with his departure from the show), hasn't worked a great deal outside of "Bones," but Hanson kept his word and brought Addy back for the final two seasons. They even managed to finesse an upbeat bit of closure for the brainwashed character, which hopefully assuaged some fans' dismay over his abruptly altered arc.

You've got to give Millegan a load of credit: Many actors would've groused to the press about getting unexpectedly dumped from a popular series, but he handled his character's fate graciously. He also credited the professional structure of working as a series regular on "Bones" as a tremendous aid in helping him cope with his condition. So good on Hanson for doing right by the actor and his character. Now here's hoping some astute casting director will bring Millegan back into our living rooms on a new series. He's a distinctively talented actor. We need more Millegan!