A poorly-timed injury has meant a last-minute rewrite for The Big Bang Theory.

Over the weekend, actress Kaley Cuoco —who plays Penny on the hit comedy—broke her leg during a horseback riding accident.

Although Cuoco’s rep claims “she’s scheduled to make a full recovery,” the CBS star – who is still in a Los Angeles hospital – will be forced to miss the show’s taping on Tuesday. That means Kaley will be completely written out of the entire episode.

The series will have a pre-scheduled break next week.

The Big Bang Theory – which moves to Thursdays this fall – returns on September 23.

(To get a look at TV Envy’s Fall 2010 Programming Schedule, click here.)