During Week 3, Bortles made his NFL debut when he came in relief of Chad Henne in the second half of a 44–17 blowout loss to the Indianapolis Colts. He went on to complete 14-of-24 passes for 223 yards, two touchdowns, and two interceptions. Following the game, head coach Gus Bradley named Bortles the starter going forward. In the next game, Bortles made his first NFL start against the San Diego Chargers. He ended the game 29-of-37 for 253 yards, one touchdown, and two interceptions in a 33–14 road loss. His 78. 4 percent completion percentage set a record for a rookie quarterback's first start. Two weeks later against the Tennessee Titans, he produced 336 yards on 32-of-46 passes (three franchise rookie records), but the Jaguars lost 14–16 due to a blocked field goal. During Week 13 against the New York Giants, Bortles threw for 194 yards, with one touchdown and no interceptions and 68 rushing yards in the Jaguars' largest comeback win in franchise history. They narrowly won 25–24 after trailing by 21 points. Three weeks later, he led the Jaguars to a Thursday Night Football 21-13 victory over the Titans. He completed 13 of 26 passes for a touchdown and no interceptions along with 50 rushing yards.