The gales of change are gusting in the Windy City, as the Chicago Bears have benched Mike Glennon and announced that rookie Mitchell Trubisky will take over as their new signal caller in Week 5.

Chicago picked Trubisky with the second overall selection of the 2017 NFL Draft. It was one of the headline moves of the draft as Chicago paid a steep price to move up one spot to land the former North Carolina Tar Heel.

The move was surprising, not just for the picks they gave up to trade up a single spot, but because the Bears had just inked Glennon to a three-year, $45 million contract ($18.5 million guaranteed), making him their apparent starting quarterback for the near future. But here we are, just four games in, and Chicago is ready to call it quits on the Glennon experiment.

With Glennon hitting the bench, what can we expect from Trubisky and the rest of the Bears' offense over the remainder of the season?

The Truth About Trubisky

The 6'3", 209-pound Trubisky set single-season school records for passing yards (4,056) and touchdowns (30) for North Carolina in 2016, completing an impressive 68% of his passes along the way. His completion rate over the course of his career was 68.9%, which is tied with Derek Carr's college mark and is superior to the career marks established by Marcus Mariota (68.3%) and fellow rookie Deshaun Watson (67.6%), both of whom have had success in the NFL early on in their careers.

Trubisky also had a final-season average yards per attempt (AYA) of 9.2. Our Jim Sannes has studied which college stats make for a successful NFL quarterback, and Trubisky is right near the success threshold of 9.3 AYA.

Those numbers were enough to catch the eye of Bears brass, but it's important to note that Trubisky had only one season as a starter. That's significant because in Sannes' study, one of the more telling stats was the sheer amount of college starts a quarterback made, with at least 36 being a good amount of college experience -- a number Trubisky falls well short of.

Here are his year-by-year numbers from his three college campaigns.

Trubisky certainly excelled in his final college campaign, but 572 pass attempts is a very small sample. For reference, using the two quarterbacks we mentioned earlier, Watson threw 1,207 passes at Clemson while Mariota attempted 1,167 throws for Oregon.

During the preseason, Bears coach John Fox compared Trubisky to Tim Tebow, but working from Sannes' data, the closest comparison as a prospect is Mark Sanchez, who posted a final-season AYA of 8.8 at Southern Cal.

What About Now?

Bears fans are hoping Trubisky is the the long-term answer at the quarterback position, but what about this season?

Could Trubisky have the type of impact we've seen from Watson, who has injected life into what was a stale Houston Texans offense? Or will it more resemble the trainwreck we witnessed from the Los Angeles Rams when they switched to rookie quarterback Jared Goff part way through the 2016 season, and he finished with just five touchdowns and seven interceptions?

One big factor working against the Bears' rookie is the lack of playmakers surrounding him. While Watson has one of the game's best wide receivers in DeAndre Hopkins to throw to, Trubisky's top receiving option will be Kendall Wright, a player who has averaged 510 yards receiving over his past three seasons. Even Goff, in his nightmare rookie campaign, had 1,000-yard receiver Kenny Britt out wide.

It's hard to get excited about Trubisky's fantasy prospects when you look at the numbers his receivers have put up through four games.

There is also reason to believe the Bears will be more conservative and throw less with a rookie under center. Looking at two of the most recent examples of teams switching quarterbacks mid-season, the 2016 Rams went from 35 attempts per game under Case Keenum to 30 attempts per game under Goff. Last year, the Denver Broncos dropped to 27 attempts per game under rookie Paxton Lynch from 36 per game with Trevor Siemian starting.

The good news is, as far as efficiency goes, it can't get much worse for the Bears -- maybe that's not good news, but you get it. Among quarterbacks with at least 80 attempts on the season, Glennon had an AYA of 5.0, the third-worst mark in the league.

That lack of efficiency is also evident when looking at Net Expected Points (NEP), our in-house metric which measures the value added or lost on each play relative to the historical expectation level. Through four games, among the 32 passers with at least 50 drop backs this season, Glennon ranks 28th in Passing NEP per drop back.

While expectations should be kept in check for the rookie quarterback, Trubisky would have to be among the league's very worst quarterbacks in order not to be an improvement on Glennon. And even if he's as bad as Glennon, there's probably an argument to be made that letting the rookie play could help him in the long run (see: Goff, Jared).

Boost for the Backs

The biggest fantasy beneficiaries could be the two running backs.

Despite Chicago's lackluster passing game, the offense has been able to support two good fantasy runners thus far. Jordan Howard and Tarik Cohen are holding their own as the overall RB10 and RB22, respectively, in standard leagues. If Trubisky can help the Bears' offense, which ranks 23rd in overall yards and 29th in points scored, improve to even league-average levels, the running backs will definitely benefit.

More yards and more offense means more red zone opportunities for the Bears' backs (and everyone else). Even without the benefit of increased looks in the red zone, Howard and Cohen may be in line for more rushing work. As shown already, passing attempts tend to go down when a rookie passer goes in, meaning rushing attempts go up.

While not a huge boost to their bottom line, this move seems to bode well for Howard and Cohen for the rest of the season.

Conclusion

Don't expect to see Trubisky start lighting it up from a fantasy perspective. That's especially true in the early going as the Bears face some tough tests in the next three weeks -- Minnesota, Baltimore and Carolina are difficult matchups, with the Ravens and Panthers ranking inside the top 10 in pass defense DVOA, according to Football Outsiders. But Trubisky could settle in as a streaming option for fantasy purposes once he gets his ears wet in the NFL, with his running ability helping his cause.

Meanwhile, the Bears' wide receivers have been unusable through four weeks, with no Chicago wideout ranking among the top 50 fantasy receivers in standard formats. We shouldn't anticipate a big jump in production, and guys like Kendall Wright and Deonte Thompson can remain on the waiver wire until we see this offense start having some success through the air.

The best news here is for Bears fans, who have been starving for decades for a true star at the quarterback position, and starting this week, they'll get to see if Mitchell Trubisky is the savior they've been waiting for.