It's not often that a television series will exclude one of its main characters, but The Big Bang Theory didn't have a choice when the actress who plays Penny was injured on one of her off days. Kaley Cuoco is the only main cast member that wasn't present for every episode of the show. She was unable to return to set during the filming of Season 4 while she recovered from a severe injury that left her hospitalized.
Cuoco's injury was unexpected and the writers of The Big Bang Theory had to figure out how this obstacle should affect Penny's role in the show. This led to her being excluded from a couple of episodes, but with some creative thinking she was able to return to filming while still in recovery.
Which Episodes of The Big Bang Theory Didn't Feature Penny?
Kaley Cuoco was absent for two episodes early in Season 4 of The Big Bang Theory. She was missing in Episode 5, "The Desperation Emanation," and Episode 6, "The Irish Pub Formulation." At this point in the show, Penny and Leonard were no longer dating so it was easy to avoid crossing their storylines. In "The Desperation Emanation," Leonard was feeling unhappy about being single and invoked the Girlfriend Pact with Howard, who had just rekindled his relationship with Bernadette. The couple set Leonard up with one of Bernadette's friends, but she turned out to be a bad match.
"The Irish Pub Formulation" introduced a new relationship for Leonard with Raj's sister, Priya. The episode was mainly focused on Leonard and Priya secretly getting together behind Raj's back. Penny was not mentioned in the episode as most of the discussion centered on the male characters betraying each other in various ways.
Why Was Kaley Cuoco Absent From Filming?
It's unusual for a main character to be absent without explanation, but Cuoco had a pretty good reason for not being there. Cuoco is an avid horse rider and had a freak accident during a weekend riding lesson. In an interview with Ellen Degeneres, Cuoco explained that her horse unexpectedly spooked and she fell off the horse but didn't get hurt. Unfortunately, the horse was still nervous and tried to get away by jumping over Cuoco and accidentally landed on her leg. The impact broke the bone in her leg and she was rushed to the hospital. Cuoco ended up spending two weeks in the hospital and had to undergo surgery to have metal bars inserted in her leg. She then had to wear a cast on her leg and foot while recovering from the surgery.
How Did The Big Bang Theory Handle Penny's Absence?
The Big Bang Theory didn't actually acknowledge Penny's absence in the episodes she missed. Both "The Desperation Emanation" and "The Irish Pub Formulation" were focused mainly on Leonard's dating life and made no mention of Penny. Cuoco said that she assumed the writers would find a way to write her injury into the show, but they decided to hide it instead.
Penny was still working as a waitress at The Cheesecake Factory at the time, but Cuoco couldn't film any scenes that would show her injured leg. She was only filmed from the waist up to hide the cast on her foot once she returned to film the rest of the season. This meant that Penny could only work as a bartender until Cuoco's leg was healed since the bar covered the bottom half of her body. Penny's absence came at a convenient time since she and Leonard were broken up, but the show had a noticeable difference in tone without her spirited personality.