Chris Haston / NBC
Abruptly departed: Christopher Meloni
Played: Detective Elliot Stabler
Lasted: Twelve seasons (1999-2011)
Why he left: The star left after contract negotiations fell through between him and the network. Mariska Hargitay, who signed on for a reduced role, further throws the stalwart series into disarray.
How it went down on air: While the network is still searching for big name replacements for its stars, NBC has since signed on two new detectives who will be played by Kelli Giddish ("Chase") and Danny Pino ("Cold Case").