Even with a midseason return and a shorter run this time, Dana Delany is happy her latest series still has life.

It actually can be considered a new life, since the ABC medical mystery “Body of Proof” will reflect significant changes as its third season starts at 10 tonight. Delany’s Dr. Megan Hunt will be without several colleagues who were present from the show’s start: Peter Dunlop (Nicholas Bishop), her investigator, who was stabbed by an enemy of Megan’s in the Season 2 finale, and homicide detectives Bud Morris and Samantha Baker (John Carroll Lynch, Sonja Sohn).

Police work will remain a factor in “Body of Proof,” though … a bigger factor, in fact, given the main cast addition.

Mark Valley (“Human Target,” “Boston Legal”) worked previously with Delany on the short-lived Fox serial “Pasadena,” and their reunion makes him Tommy Sullivan, an investigator with whom Megan has a personal past – a fact reinforced by their playfully edgy exchanges.

Jeri Ryan and Geoffrey Arend are among the show’s original co-stars who remain, while Elyes Gabel (“Game of Thrones”) also joins the regular cast as Sullivan’s partner.

“It’s odd,” the lively, friendly Delany admits of adjusting to the revamped “Body of Proof” approach. “I feel it’s more of a ‘two-hander’ now, since a lot of it is me and Mark (debating) the science versus the police work. I’m working more than ever now. The hours just seem to be longer.”

A reduced budget also was a condition of “Body of Proof” getting another renewal. “Chris Murphey was new to television when he created the show,” Delany says, “so I don’t think he understood that you have to create a world you can continue with. You have to have all these moving parts that work together. When [new executive producer and ‘24’ veteran] Evan Katz came in, he wanted to clarify everything and lay out people’s roles more.”

As an example, Delany points to Ryan’s character, Chief Medical Examiner Kate Murphy. “Being the overseer, she would not be in the autopsy room that much, so she’s now doing what a lot of chief medical examiners do. She’s much more the political animal who deals with the city, the mayor, that kind of thing.”

Megan Hunt has displayed a certain sass right from the beginning of “Body of Proof,” and Delany appreciates that Valley’s arrival permits her to display even more of it.

“I joke about it, but it’s true: He reminds me of me,” she says. “We are very similar in how we approach the work, that it just make sense. I think he loves acting the way I love acting.

“We still get a kick out of it and try to find the humor in it,” Delany adds. “If I do anything that’s not in the script, he will come back with something. He’ll call me on it. I really cannot get away with anything with Mark, and it keeps me on my toes. We will never be satisfied until we get it right. I really like the feeling that I have someone who’s going to match me on that – and also who’s going to challenge me, because Mark is not afraid of me in the least.”

“China Beach” Emmy winner Delany isn’t afraid to voice her own challenges.

“We’ve had a couple of scripts this season where I did not agree with the ending,” she reports. “I would talk to the writers and say, ‘Wouldn’t it be much more interesting if this person killed that person for this reason?’ Sometimes they agree, and sometimes they don’t.”

While she welcomes Valley on board, Delany also laments the absence of her “Body of Proof” comrades no longer there, especially since they collectively got the show on its feet by filming the first season in Rhode Island. (It’s been shot in Southern California since.)

“I’m a bit of a vagabond, anyway,” Delany notes, “so I like a new experience. I’ve been like this since I was a kid. I’d go to summer camp kicking and screaming, then by the end of the summer, I didn’t want to leave. Being on location is like that, too. I did not want to go to Rhode Island, I didn’t want to leave my house, I had to find an apartment and a car and a hair colorist. You have to re-create your infrastructure.”