INDIANAPOLIS -- The Indianapolis Colts called it a move based on the long-term future of their backup quarterback position. But the reality is the trade to acquire Jacoby Brissett from the New England Patriots on Sept. 2 was out of necessity.

The Colts spent the offseason hoping that Scott Tolzien would show signs of being able to run the first-team offense in Andrew Luck's absence. But the hope waned as each Tolzien pass was off target or underthrown during offseason workouts, training camp, preseason games and the first three quarters of the regular season at the Los Angeles Rams.

The opportunity to trade underperforming receiver Phillip Dorsett for Brissett was too good pass up. The Colts weren't going to be able to tread water while Luck remained out with Tolzien continuing to start at quarterback. They would have sunk. Indianapolis could have been winless at this point had Brissett not replaced Tolzien as the starter in Week 2.

The bumps have been there for Brissett. That's expected, though, when you take into consideration that he has started four games despite being on the roster for only six weeks. What Brissett has given the Colts is a jolt of life at quarterback because he plays with confidence, has command of the offense and already has the respect of his teammates.

"That's the thing about Jacoby, he doesn't see himself as a backup quarterback," running back Robert Turbin said. "That's how you have to think. You don't give yourself the best chance to be great when you think that way. Jacoby is that way. He approaches it like he's a starter and like he's a leader. He's got all the tools to do that.

"He plays with confidence, he plays with swag, he believes and it shows. It shows in practice, it shows even the way he talks to the team like he's not afraid of the spotlight. He's not afraid to be a leader. He doesn't hide from the leadership department."

It's challenging enough for any backup quarterback to have to step in during an emergency situation. It's even more challenging when you have to do it after fewer than 10 practices with your new team. Brissett replaced the ineffective Tolzien just a week after arriving in Indianapolis, in the fourth quarter of the Colts' 46-9 blowout loss to the Rams after Tolzien threw two interceptions that were returned for touchdowns.

Brissett was named the starter days later, and he hasn't looked back. He's 75-of-124 for 946 yards with two touchdowns and three interceptions in his four games as a starter.

"It's like watching 'Major League.' All he's missing is the glasses with tape right here [like pitcher Ricky Vaughn]," Colts coach Chuck Pagano said. "He's got a little Wild Thing in him, but he's awesome. He's an all-star. He's a great teammate. Those guys in that locker room would just [say] -- this guy just -- he's got it. He's got the 'it' factor. He's a talented, talented guy, but he's got the 'it' factor. He makes people -- he brings energy, he brings juice."

There have been two common themes inside the Colts organization when you ask what stands out about Brissett: mental toughness and confidence.

He doesn't carry himself like a 23-year-old second-year quarterback when you talk to him. Offensive lineman Jack Mewhort said Brissett didn't go into the huddle the first time he took the field with a "deer in the headlights" look on his face.

"You can tell the guy is a professional," Mewhort said. "That's inherited, and he has it inside of him. He's a quarterback by trade. You can tell that about him. He inspires that confidence in the huddle and as an offensive lineman when you look in a guy's eyes and it's third-and-forever and you look at him and he's not shaken at all. That's what you want to see out of a quarterback. He's got that. Look where he was at before he came here."

Mewhort is referring to Brissett's rookie season in New England, where he learned how to play in the league from Bill Belichick and Tom Brady, arguably the NFL's greatest coach and quarterback. Brissett played in only three games during his rookie year because he was third on the depth chart behind Brady and Jimmy Garoppolo. But it's the things that don't show up on the stat sheet that helped Brissett.

Professionalism. Film study. Practice habits. Nutrition.

"I think it's huge," former Colts quarterback and current ESPN NFL analyst Matt Hasselbeck said. "I've always said what you experience as a rookie, the team you're on and the position group you're with, will set the standard for what you think it means to be a pro. Randy Moss came in with Cris Carter and Denny Green in Minnesota and that's how he thought that's how the NFL was. For Brissett, he shows up and watches how Tom Brady does it every day and he sees how Bill runs the team. You couldn't ask for a better situation."

Brissett's mental toughness was tested in overtime in Week 5 against the San Francisco 49ers. The Colts took the opening kickoff and got down to San Francisco's 8-yard line when Brissett threw an interception. It was the second time in just four games that the quarterback was picked off in overtime. His interception on the first play of OT cost the Colts the game in their Week 2 loss to the Arizona Cardinals.

Brissett said he went to the sideline "pissed" about his mistake, and he could have wilted after that. But the defense held the 49ers and the Colts won on Adam Vinatieri's 51-yard field goal on their next possession.

"[The interception] can be something that throws a guy off the rest of the game, but he was able to come back," offensive coordinator Rob Chudzinski said. "And it wasn't always pretty, and it isn't always pretty. He's still learning. He has a lot of things he can work on.

"Quarterbacks are going to make mistakes, and they're going to make big mistakes through the course of their career. And how they bounce back in games from those things, how they bounce back during the course of the season from those things, is really what determines how good they end up being."

Luck continues to progress toward making his 2017 debut following right shoulder surgery in January. Brissett has proved that he's a valuable backup quarterback in case something happens to Luck and that the Colts can potentially use him in a trade to help improve their roster.

"He came in, had zero ego, he just wanted to get the job done," Colts receiver Kamar Aiken said. "He's been upbeat, positive and an overall good person. We already knew he could come in and do the job because we saw him when he was in New England. Word gets around quick in this league. It's not like he came in blind and nobody knew about him. They know how to coach guys over there in New England."