Samuel James Sam Witwicky is portrayed by Shia LaBeouf in the first three films in the Transformers film series. In early versions of the script, Sam had the nickname Spike (the name of the main character in the original Transformers series). This idea was later scrapped because, according to writer Roberto Orci, these nicknames were appropriate for a mechanic and an oil rig worker in the animated series, occupations in which the characters did not work in the film. According to Roberto Orci, the character of Sam was written as a 2007 version of Marty McFly . Sam Witwicky did not return for the fourth film; his character is later replaced by Cade Yeager (portrayed by Mark Wahlberg).