Marshall was instrumental in Auburn's turnaround from a 3–9 season in 2012 to beginning the 2013 season 9–1 while beating the Ole Miss Rebels, then ranked #24 in the AP Poll and #6 Texas A&M Aggies. On November 16, 2013, Marshall was the quarterback behind a play known as "The Prayer at Jordan-Hare" when he threw a 73-yard Hail Mary touchdown pass to Ricardo Louis on a 4th-and-18 with 36 seconds left to defeat the Georgia Bulldogs. On November 30, 2013, Marshall threw the game-tying touchdown pass with 32 seconds remaining in the epic 2013 Iron Bowl to even the score 28–28. Auburn won the game on a 109-yard touchdown return from an Alabama missed field goal. The team later went on to win the SEC Championship, and earned a berth in the 2014 BCS National Championship Game and lost. After his time at Auburn, he decided to enter the 2015 NFL Draft. Statistics Although he was invited to the 2015 Senior Bowl as a quarterback, Marshall announced during the week that he would move to cornerback in his attempt for an NFL career. Marshall was signed by the Jacksonville Jaguars as a free-agent after going undrafted in the 2015 NFL Draft He played primarily on special teams including returning kickoffs for most of the season but saw his role on defense increase the last four weeks of the season. He started his first NFL game week 17 against the Houston Texans. On September 3, 2016, he was released by the Jaguars. He was signed to the Jaguars' practice squad the next day. On October 12, 2016, Marshall was signed by the Jets off of the Jaguars' practice squad. On April 14, 2017, Marshall was suspended four games for testing positive on performance-enhancing drugs. Marshall was waived by the Jets on May 4, 2017. On November 2, 2017, Marshall was signed to the Arizona Rattlers of the Indoor Football League, alongside his brother, defensive back Antonio Marshall. However, both brothers departed the team before the 2018 season began, with Nick signing in the CFL. In April 2018, Marshall signed with the Saskatchewan Roughriders of the Canadian Football League (CFL). After the preseason, Marshall was named a starter at cornerback for the 2018 season. In Week 1 against the Toronto Argonauts, Marshall recorded an interception for a touchdown for the game-winning points in the 27–19 victory, but was subsequently placed on the six-game injured list following a broken finger. Marshall recorded another 'pick-six' in addition to a rushing touchdown in the Riders Week 10 win over the Calgary Stampeders.