Career
After playing college football for Georgia, he was drafted by the Vikings in the third round of the 2009 NFL Draft. Allen made his NFL debut in week 7 against the Pittsburgh Steelers due to an injury to starting cornerback Antoine Winfield. In the game, Allen made two key fourth quarter plays.
He first made a touchdown-saving tackle on a kick return by Stefan Logan.
Later in the drive he caused a fumble on Steelers quarterback Ben Roethlisberger, resulting in a fourth down. In week 11 against the Seattle Seahawks, Allen intercepted a pass from Matt Hasselbeck for his first NFL interception.
He was placed on injured reserve at the end of the 2011 season due to a concussion. After three seasons of play, he announced his retirement from the NFL on May 30, 2012.