INDIANAPOLIS -- Indianapolis Colts quarterback Jacoby Brissett has felt the pressure in his NFL career.

As a rookie, he had to start in place of future first-ballot Hall of Famer Tom Brady in New England. Brissett also started 15 games and learned the playbook on the fly after the Colts acquired him from the Patriots a week before the start of the regular season in 2017.

Now, Brissett is about to endure the toughest challenge since he took over as the starter in the second half of that Week 1 game at the Los Angeles Rams more than two years ago.

He has to try to keep the Colts in the playoff race without their top skill position players at his disposal. The Colts trail first-place Houston by two games in the AFC South and are a game behind Pittsburgh, which owns the tiebreaker over Indianapolis, for the final playoff spot in the AFC.

The Colts, who were once 5-2, have dropped four of their past five games to fall to 6-6. They play at Tampa Bay on Sunday (1 p.m. ET, CBS).

The challenge is a daunting one for Brissett. They are without receivers T.Y. Hilton (calf) and Parris Campbell (hand), tight end Eric Ebron (ankle) and running back Marlon Mack (hand).

That’s a combined 1,155 yards receiving, 914 yards rushing and 15 touchdowns missing from a Colts offense that has been inconsistent and unreliable.

“I know how Jacoby feels because he felt the same way I felt when I played; my guys are my guys and we’re going to win with whoever we have,” Colts coach Frank Reich said. “… Jacoby has belief in our receivers. Now that being said, just a general statement about the quarterback position is we all know what the quarterback position entails. You’re 100 percent reliant on everybody around you and it all works together.”

The Colts haven’t had any discussion about placing Hilton, their most valuable offensive player, on season-ending injured reserve because they’re hopeful he’ll be able to return. Ebron is out for the season. Mack has missed the past two games and Campbell is getting closer to returning after practicing last week. Reich said the plan is for the Colts to add another receiver to the roster this week; they were down to three at that position after Chester Rogers was lost for the season to a knee injury in the first half against Tennessee on Sunday.

This season has been more flash than consistency for Brissett, who took the vast majority of first-team snaps this past offseason. And fair or not, the missteps by the offense often lead to the finger being pointed back at him. Two major strengths of former starter Andrew Luck were fourth-quarter comebacks and an ability to raise the play of his teammates. Brissett, with all the injuries surrounding him, has struggled to do that.

Brissett threw for 319 yards on Sunday, with 109 yards going to receiver Zach Pascal, but he had two errant throws that cost the Colts 10 points. He threw an interception after holding the ball too long, overthrowing tight end Jack Doyle deep in their own territory. He was picked off again after he tried to force the ball down the field to Pascal after Tennessee took a seven-point lead in the fourth quarter.

“It was a bad decision,” Brissett said.

Calling it a “bad decision” was the theme of Brissett’s postgame news conference Sunday. He used that comment on three separate occasions.

“Jacoby made a ton of good plays,” Reich said. “Threw for a lot of yards, but really interesting, the week before, we could run it. But that’s not good enough; we need chunk plays too. We got all kind of chunk plays the other day and we lost [to the Titans]. That’s why it’s a complete team game in all three phases. I thought Jacoby made a ton of plays. Had a couple of plays he would like back. But we all do.”

In the past six games in which Brissett has played the whole game, the Colts have scored more than 20 points just twice. He hasn’t thrown for more than one touchdown in a game since he had four touchdown passes against Houston on Oct. 20.

“As an offense, we definitely have to do better,” running back Nyheim Hines said. “As an offense we have to score more points. ... Execution. You can say it’s playcalling or whatever, but it’s not really that. You can call whatever play you want, but as a team, it only works if the players work. Honestly, by a position group we have to do better. Running backs, receivers, QB, O-line -- we have to execute. It doesn’t matter what play is called.”

The Colts can’t suddenly flip a switch and acquire players to help the offense. It's too late in the season.

Reich talked confidently about Brissett on Monday. Now it's up to the quarterback to show he’s the right person to be the starter of the future.

“The failures we’ve had as an offense, and not just as an offense and as a team, it’s not been on any one guy,” Reich said. “I know we’ve lost four of the last five; we all want answers. Those answers start with me as a coach and I have to do a better job getting guys ready. We have to do a better job on offense of having the best plan, scoring more points. I have confidence in the players we have. There’s no excuses there.”