On September 8, 2013, Shelby recorded his first-career sack, which included a forced fumble against the Cleveland Browns. The next week on September 15, he would strip-sack Andrew Luck for his second sack and forced fumble on the season. On September 30, 2013, he made his first-career start in his second season against the New Orleans Saints. Shelby finished his second NFL season with a season-high 34 tackles, two forced fumbles and 2.5 sacks.
