Coach Gus Bradley named Gabbert the starter Thursday, two days before the Jaguars face the New York Jets in their second preseason game.
Gabbert played the first four series in the team's preseason opener against Miami, completing 5 of 10 passes for 19 yards. He had two passes dropped and another one go off a fullback's hands for an interception.
"We feel like he needs the reps right now considering he missed six games last year at the end," Bradley said, referring to the forearm injury that ended Gabbert's 2012 season. "He got 17 snaps in the opener, and we just felt like we'd like to increase it this week and get a better chance to evaluate where he's at."
Chad Henne, who's competing with Gabbert for the starting job, also will see playing time with the first-team offense. Henne got some work with the starters against the Dolphins, completing 8 of 11 passes for 87 yards.
Both quarterbacks should benefit from the return of three starters. The Jaguars will have center Brad Meester, running back Maurice Jones-Drew and receiver Justin Blackmon back on the field against the Jets.
"It's going to be a big difference having those guys back," Gabbert said. "They're anxious and ready to play. ... It will be the old crew back there playing ball."
Bradley has rotated both quarterbacks throughout training camp, giving Gabbert and Henne plenty of work with the starters while trying to figure out who will win the job.
Many believe it will be Gabbert, who's younger, more mobile and coming off consecutive seasons in which Jacksonville had issues around him. Gabbert had no offseason as a rookie because of the NFL lockout, was thrown into the starting lineup in Week 3 and played with one of the worst receiving corps in the league.
He was expected to show significant improvement last year, but he played behind a patchwork offensive line and with two young receivers in Shorts and Blackmon. Jacksonville also lost Jones-Drew to a season-ending foot injury in October.
So Bradley and new general manager Dave Caldwell believe it's difficult to truly evaluate Gabbert's viability as an NFL starter.
"I know that conventional wisdom tells us that, 'Hey, we start one and the other one starts,'" Bradley said. "But there's a lot of things that we do that aren't conventional. I know maybe some of you felt that way. But to us it made sense in our evaluation process.
"We just looked at the whole thing and said, 'OK, he had 17 reps, didn't play the last six games of the season and we just need to get more looks at him.' Knowing our situation, we just took that approach. This isn't any determining factor. We're just still figuring the whole thing out."
Gabbert was the 10th overall pick in the 2011 draft. The former Missouri standout has completed 54 percent of his passes for 3,876 yards, with 21 touchdowns and 17 interceptions, in two seasons. He is 5-19 as a starter.
"I'm just looking at it as another opportunity to go out there and prove to the coaches and prove to the guys on the team that I'm the right guy for the position," Gabbert said. "But it's also another opportunity to learn our offense, another chance to go against a different defense and perfect the things we've been working on all week."
Henne handled the news well, saying he understands Bradley's plan.
"We've been splitting the reps in practice again," Henne said. "Nothing's really changed. And for me, it's just take full advantage of what I have and show them what I can do on the field."