LAKE FOREST, Ill. -- The Chicago Bears poured ample resources into fixing a team that won just 14 games in three seasons under John Fox. It started with signing a No. 1 wide receiver in Allen Robinson in free agency and ended with a splash by trading for perhaps the best defensive player in the game, Khalil Mack, who got a new deal that includes $90 million guaranteed.

The Bears' defense, which finished ninth in the NFL last season, now has a game-changer in Mack, a promising rookie middle linebacker in Roquan Smith and an emerging talent in Leonard Floyd. The offense stocked up on weapons beyond just Robinson, signing tight end Trey Burton and receiver Taylor Gabriel and drafting Anthony Miller.

But for all the attention paid to the new faces, the most important player on the roster has not changed.

The Bears, who have not been to the playoffs since 2010, will go only as far as second-year quarterback Mitchell Trubisky takes them.

If the Bears are to transform into a perennial postseason qualifier, Trubisky has to develop into an above-average quarterback in new head coach Matt Nagy’s version of Andy Reid’s West Coast offense.

"This is a growing process, and I’m very positive about where we’re headed," Trubisky said Wednesday.

How soon the Bears reach their final destination is up for debate.

Trubisky, the No. 2 pick in the 2017 draft, flashed some promise as a rookie last season in starting the Bears’ final 12 games.

But Chicago’s offense last season was rudimentary at best.

Fast-forward to Week 2 versus the Seattle Seahawks on Monday night, and the Bears' new offense, one that Nagy brought with him from Kansas City, is entirely different.

"Trubisky is still a very young player," ESPN NFL Insider Matt Bowen said. "I know everyone wants immediate results -- I understand that -- and people are going to compare Mitchell Trubisky’s Week 1 to [Kansas City Chiefs starting quarterback] Patrick Mahomes’ Week 1. Mahomes [who had four touchdown passes] had much more success. People are going to compare those two players for a long time, especially since now they are playing the same system. But remember, Patrick Mahomes had an entire year with Andy Reid last season. Mitchell Trubisky had one offseason and very limited reps in the preseason. This is a process."

Trubisky teased the Bears’ restless fan base with a brilliant first half in Chicago’s 24-23 loss to Green Bay in Week 1. While the Packers scuffled on offense -- Aaron Rodgers left the game for a period of time with an injury -- Trubisky led the Bears on consecutive scoring drives to open the game. At halftime, Trubisky had a blistering stat line: 8-of-9 passing for 99 yards (112.5 quarterback rating) and a 2-yard touchdown run.

The second half was an entirely different story.

As Green Bay roared back behind Rodgers, Trubisky looked rushed in the pocket at times. The Bears’ offense, which was so effective in the first 30 minutes going off Nagy’s play script, missed opportunities. Many of Trubisky’s throws missed their mark. And a Bears offense that played with such poise and confidence early on began to err a little too much on the conservative side.

Trubisky finished with 23-of-35 passing for 171 yards (77.2 passer rating).

At the core of some of Trubisky’s struggles at Lambeau Field: pocket awareness.

Great quarterbacks have the rare ability to work inside the pocket, to step up or slide to improve sight lines on throws, or to wait for routes at the end of their progression to come open.

But that skill rarely materializes overnight.

And for Trubisky -- a dangerous runner in the open field -- the temptation to hit the eject button and abandon the pocket is even greater.

"I’ve got to find a kind of happy medium, and in practice, it’s going to be pocket movement, moving around defenders in the pocket and continuing to keep my eyes downfield so you can find receivers," Trubisky said.

"But I’m going to continue to use my natural ability, keep plays alive, because there could be a lot more big plays from a scramble, as well, but I’m trying to stay in the pocket and become a lot better passer in the pocket and continue to move around, very subtle movements with calm feet, to find receivers. That’d be something I’ll be working on in my career, but definitely more emphasis this week."

Nagy said the goal is to "always teach quarterbacks to be a thrower first."

"Anything that happens after that, let it happen naturally. Specifically, you’ll see some teams that want to play certain coverages that enable you to take advantage of your legs, and then we’ll know that going into the game, when that might come. But be a thrower first and then if it’s not there, use your natural instincts to take off and run and then be smart when you’re running. Once Mitchell gets those progressions down in this offense then that part will start coming more naturally."

Trubisky’s growth in the offense will take time.

The key for the 24-year-old will be tuning out outside expectations.

Bears fans are starved for a winner. The NFL’s charter franchise has been dead last in the NFC North four straight seasons. The Bears have one playoff victory since 2006.

For all the hype surrounding the Bears’ pickups of Mack and Robinson, the city understands that Trubisky is central to any sustained turnaround.

That kind of pressure can wear on a younger player.

"I can’t let any game, any play define who I am as a player or as a person," Trubisky said. "We want immediate results -- everybody, the media, the fans, myself -- but unfortunately, that’s not always part of it. So I’ve just got to continue to work, get better every single day and realize that’s the kind of level we’re at and those are the expectations.

"But I’m not going to hold any extra pressure over my head or do anything more. I’ve just got to do what I’ve got to do, and hopefully people will understand, but I think I understand the situation that I’m in and what all comes with it."