JACKSONVILLE, Fla. -- The Jaguars now have an open quarterback competition.

Head coach Doug Marrone said Thursday night that Blake Bortles -- the third overall pick in 2014 and the team's starter since Week 4 of his rookie season -- and Chad Henne will share first-team reps as Marrone searches for a starter before the season opener against Houston.

"I'm looking for someone that's going to lead this offense," Marrone said after the Jaguars' 12-8 loss to Tampa Bay at EverBank Field. "I'm not happy with the performance today. I'm not going to sit here and B.S. anyone. Everyone saw it out there. Whatever you want to call it, I'm still trying to evaluate who the best person is at that position."

Bortles was an unimpressive 8-for-13 for 65 yards in four drives against the Bucs, all of which ended in punts. He also was sacked once. He has completed 11 of 18 passes for 81 yards with no touchdowns and no interceptions in two preseason games.

Henne also got snaps with the first-team offense late in the first half Thursday; the team says the move was planned before the game. He threw two first-half passes, which were dropped in the end zone by Keelan Cole and Allen Robinson. Jacksonville trailed 12-0 at halftime.

Marrone told ESPN at halftime that he was upset with the entire offense, emphasizing he felt all 11 players struggled and not just Bortles. He sent the first team back on the field with Henne to start the third quarter. Henne finished 6-of-10 for 44 yards in two drives.

"I'll approach it the same way," Bortles said. "I'll approach tomorrow as I treated yesterday and as I treated today. I don't think anything changes from my mindset or anything there. I think it's my job to go out there and earn the respect and trust of those guys as well as the coaching staff, and that's what I'm kind of on a mission to do."

Chad Henne took the field with the Jags' first-team offense after starter Blake Bortles went 8-for-13 for 65 yards in four drives. Henne went 6-of-10 for 44 yards in two drives. Reinhold Matay/USA TODAY Sports

Aside from the second part of last Sunday's practice, Henne has worked exclusively with the second-team offense. Henne took those first-team reps last Sunday because Marrone said he wanted to rest Bortles, saying Bortles' arm "looked tired." Marrone also said the move was not made in response to the two interceptions Bortles threw in the first part of that practice. Two days later, Bortles said his arm was fine.

Bortles has had an up-and-down training camp -- with the lowlight being a five-interception practice on the first day the team was in full pads -- in what is a make-or-break season for him in Jacksonville. Bortles, who has committed the most turnovers (63) and thrown the second-most interceptions (51) in the NFL over the past three seasons, has won only 11 games as a starter and has thrown 11 pick-sixes.

The Jaguars did not bring in any quarterbacks in the offseason to compete with Bortles and instead planned on building the offense around the run game, which is why the team drafted Leonard Fournette fourth overall.

The team picked up Bortles' fifth-year option for 2018, but that's guaranteed for injury only. If the Jaguars decide Bortles is no longer their quarterback of the future they can cut him after this season without owing him any money, as long as he isn't injured.

Henne, 32, has played only one regular-season snap since Week 3 of the 2014 season. He has thrown 58 touchdowns and 63 interceptions and has made 53 starts with Miami and Jacksonville.

"I always took it as I'm always competing and never really said I'm the backup, even though that's the way it was," Henne said. "I still study hard and try to prove in practice what I can do. All I can do is to try to get myself better prepared each week."