Barnes also played for the Philadelphia Eagles, San Diego Chargers, and New York Jets.
After graduating from Miami Norland High School, barnes played college football at Florida International University in Miami, Florida where he was a 2006 All-Sun Belt Conference selection and the school's all-time sacks leader with 21.5. On April 29, 2007, he became the first player in FIU history to be drafted by a National Football League team when he was selected in the fourth round by the Baltimore Ravens.
Barnes was a promising rookie in 2007, notching 2 sacks, 1 forced fumble, and 10 solo tackles. During a 2007 preseason game, Barnes delivered a blind side hit on Philadelphia Eagles punter Saverio Rocca, knocking off his helmet. Even though officials did not penalize Barnes during the game, the league fined him $12,500 for the hit. In 2008, on a roster deep with LBs, he made a name for himself as a stand out special teams player, also making his first post-season appearance. In 2009, Barnes started the year with his first career interception (against the San Diego Chargers, his future team), but then saw no action for several games. The team finally started using him late in the season, after the defense suffering an overall lack of pass rush, and he came in and notched 3 sacks and 10 solo tackles, as well as a force fumble.
Barnes was traded to the Philadelphia Eagles in exchange for a 2011 seventh-round draft pick on September 4, 2010. He was released on October 9, after being sparsely used and posting only three tackles.
Barnes was signed by the San Diego Chargers on October 12, 2010. He made an immediate impact, notching 2 sacks on Tom Brady in a game against the New England Patriots. As a backup pass-rush specialist, he ended the season in San Diego with 4.5 sacks and 15 tackles. On July 27, 2011, the Chargers re-signed Barnes to a two-year contract.
In the 2011 season, he established himself as one of the top pass rushers on the Chargers team, starting 5 games, and notching 41 tackles, 11 sacks, and 2 forced fumbles. His best career game came against his former team, the Baltimore Ravens, on a prime-time December 18 game in San Diego, where he garnered 4 sacks against QB Joe Flacco, along with 6 total tackles.
Barnes signed a two -year contract with the New York Jets on March 18, 2013. Barnes was placed on injured reserve on October 9, 2013 after suffering a season-ending knee injury. After spending the first six weeks of 2014 on the physically unable to perform list, Barnes was activated on October 15, 2014. He was released on December 1, 2014.