The 27-year-old, who clinched the championship title in the last four seasons, was expected to be punished in Austin, Texas this weekend after using up the five power units permitted during the 2014 Formula 1 season.
A statement from the governing body said: "The sixth complete power unit has been used by car one. This is in breach of Article 28.4 of the FIA Formula One Sporting Regulations.
"The requirement to start the race from the pit lane is imposed in accordance with Article 28.4 c). The team notified the technical delegate of the change to the power unit elements on Monday, October 27 at 17:41."
Vettel, who clocked the seventh-fastest time in today's first practice session, could miss qualifying as a result of his pit-lane start, but the team are yet to confirm the driver's plans.