10 Of The Best Casting Change Decisions In Recent Television History

All in the name of "chemistry."

1. Parks and Rec: Paul Scheneider replaced by Adam Scott and Rob Lowe

A two-fer! Schneider, who played city-planner Mark Brendanawicz, left this hit NBC sitcom in its second season to pursue film roles. Fortunately for Pawnee's leading ladies, Leslie Knope and Ann Perkins (played by Amy Poehler and Rashida Jones), their love interests Chris Traeger and Ben Wyatt swooped in from Indianapolis and truly stole the show. Unfortunately, Ann and Chris are leaving Pawnee this season to raise their unborn child in Indianapolis. This, in the words of Chris, is literally the saddest news ever.

2. Bones: Jonathan Adams replaced by Tamara Taylor

Dr. Daniel Goodman, who was the head of the Forensic Division at Jeffersonian Institute was replaced after the first season hit Fox show. Dr. Camille Saroyan (who was not supposed to become a permanent cast member as it was originally planned to kill her off) was introduced as his successor. She went on to become a multidimensional character who had more appeal and a more hands-on character in comparison to Dr. Goodman's absent and administrative role.

3. Castle: Ruben Santiago-Hudson replaced by Penny Johnson Jerald

After the tragic death of Captain Roy Montgomery in the season 3 finale, ABC crime-drama Castle needed to recast its precinct's captain. Strict and by-the-book, Captain Victoria Gates enters the cast and added a new tone to the show (she goes by "Sir").

4. Psych: Anne Dudek replaced by Maggie Lawson

Psych fans rejoiced when fake psychic Shawn Spencer and Detective Juliet O'Hara finally got together in season five of USA's longest running series. However, this never would have happened if Anne Dudek hadn't been replaced after the pilot episode (she ended up on Covert Affairs). I'm sure that Maggie and her real-life boyfriend James Roday, who plays Shawn, are very happy with this casting decision.

5. Modern Family: Ella Hiller and Jaden Hiller replaced by Aubrey Anderson-Emmons

ABC's Emmy and Golden Globe-winning darling Modern Family is best known for it's dry wit and memorable and hilarious characters. After the Hiller twins "retired" from acting due to disinterest, recasting Lily with Aubrey was one of the best decisions in recent TV history. She nails every line and has completely stolen scenes from her award-winning and seasoned co-stars.

6. New Girl: Damon Wayans, Jr. replaced by Lamorne Morris

Wayans filmed the New Girl pilot as Coach not knowing if his other show, Happy Endings, would be picked up for another season. When it was, Wayans was replaced by Lamorne Morris as a new character, Winston. However, after Happy Endings was cancelled last spring, Wayans came back as a guest star on New Girl this fall and it was recently announced that he was staying the rest of the season.

7. Big Bang Theory: Amanda Walsh replaced by Kaley Cuoco

TV's #1 comedy originally had Amanda Walsh as "Katie" in an unaired and considerably different pilot. Although the characters of Sheldon and Leonard (portrayed by Jim Parsons and Johnny Galecki, respectively) were kept for the second pilot, Kaley Cuoco was brought in to play the lead female role of "Penny".

Additionally, the introduction of Melissa Rauch and Mayim Bialik (Bernadette and Amy) as love interests for Howard and Sheldon has been another great casting decision, with Bialik receiving two Emmy Nominations for the role. They both have moved to starring roles on the series.

8. Grey's Anatomy: Replacements all around

Grey's Anatomy has had more casting changes than any show in recent history. With such a large cast and 10 years on the air, show creator Shonda Rhimes really likes to change it up. Some standouts include the addition (and killing off!) of Dr. McDreamy, and the controversial firing of Isaiah Washington as Christina Yang's love interest, which was eventually replaced with Kevin McKidd's Owen Hunt. In addition, the killing off of George O'Malley and Lexie Grey, the departure of Izzie Stevens and the additions of Dr. Kepner, Dr. Avery and Dr. Robbins have all impacted the popular and evolving drama.

9. Private Practice: Merrin Dungey replaced by Audra McDonald

After filming a backdoor pilot for Grey's Anatomy, Kate Walsh's character Dr. Addison Montgomery's best friend Naomi Bennett, portrayed by Merrin Dungey was replaced by five time Tony winner Audra McDonald for reasons unknown.

10. How I Met Your Mother: "The Mother" replaced by Cristin Milioti

After years and years of hearing about Ted's back story, the season 8 finale of How I Met Your Mother finally caught a glimpse of Ted's future bride. Cristin Milioti was cast as the yet-unnamed character who Ted finally meets at Barney and Robin's wedding. Many have considered her casting a great one, as she fits in well with the group (some even believe she looks like a mixture of cast-mates Alyson Hannigan and Cobie Smulders).