AUSTIN, Texas (Reuters) - Ferrari's Sebastian Vettel will have a three-place grid penalty at Sunday's U.S. Grand Prix, dealing a blow to his hopes of preventing Lewis Hamilton winning a fifth Formula One world championship.
Race stewards decided on the drop after Vettel had failed to slow sufficiently while red warning flags were waved in Friday's wet practice.
Britain's Hamilton leads Vettel by 67 points with four races remaining and the Mercedes driver will take the title on Sunday if he scores eight points more than the German.
(Reporting by Alan Baldwin, editing by Ken Ferris)
