Is Bears quarterback Mitch Trubisky ready to go?

After a preseason in which he took only three snaps and didn’t throw a pass, Trubisky’s readiness is the biggest X-factor heading into the Bears’ season opener Thursday against the Packers at Soldier Field.

Quarterbacks have been eased into the regular season before, but a third-year quarterback in a developing offense — who has started 40 games since high school — taking the preseason off? A self-proclaimed ‘‘reps guy’’ who depends on learning from experience and correcting mistakes going into the regular season with nary a pass attempt in a preseason game? That’s pretty much new territory in the NFL.

‘‘I feel really, really good with where he’s at,’’ coach Matt Nagy said after the Bears concluded the preseason Thursday against the Titans at Soldier Field. ‘‘I know he’s worked really hard. Even this past week, in meetings, just seeing where he’s grown. I think about last year to this year, where he was at and the questions that he’s asking [quarterbacks coach Dave Ragone] and [offensive coordinator Mark] Helfrich.

‘‘So we’ll see. We’ll see when he’s put to the test. We won’t really know until we get going. But I have ultimate confidence in where he’s at. I know I’m excited to see what this year is going to bring for him.’’

For the record, Trubisky was one of five NFL quarterbacks not to throw a pass in the preseason. Four of them — the Packers’ Aaron Rodgers, the Rams’ Jared Goff, the Eagles’ Carson Wentz and the Chargers’ Philip Rivers — didn’t even play a down. The Raiders’ Derek Carr (six snaps), the Saints’ Drew Brees (eight), the Panthers’ Cam Newton (11) and the Texans’ Deshaun Watson (15) made only token appearances.

In fact, the 28 quarterbacks who went through the preseason as the presumed or unquestioned starter averaged 27.9 snaps. Josh Allen, in his second season with the Bills, played 65 snaps. Jameis Winston, in his first season with new Buccaneers coach Bruce Arians, played 58. Jimmy Garoppolo, coming back from a season-ending knee injury with the 49ers, played 50. The Steelers’ Ben Roethlisberger (20), the Lions’ Matthew Stafford (33), the Falcons’ Matt Ryan (31), the Patriots’ Tom Brady (28) and Brees all played in only one preseason game.

‘‘Every quarterback’s different,’’ Bears backup Chase Daniel said. ‘‘Some want to play a lot; some don’t really care. It’s just preseason. I think we’re in a good spot, where it’s not the first year in the offense with Mitch. You’ve seen all these backup quarterbacks go down. Chad Henne [broken ankle] was the latest. RG3 [Robert Griffin III] broke his thumb. Why put your franchise out there to get hurt? It doesn’t make a lot of sense.’’

The Bears’ confidence in Trubisky’s readiness is based on three factors that sound right until they’re proved wrong: 1) Trubisky has had more practice reps than normal. 2) The practice reps he has gotten have been more intense and real-world, including the ‘‘mock game’’ practice under the lights Aug. 14 at Halas Hall. 3) His practice reps have come against Khalil Mack and the Bears’ first-team defense, which ranked No. 1 in the NFL in points allowed and yards per play last season.

It’s that last one that is the most intriguing because of the possibility that facing the Bears’ elite defense day-in and day-out has provided the offense with an opportunity many teams just can’t get. As left tackle Charles Leno said, ‘‘What’s better than going against Khalil Mack?’’

‘‘That’s a real thing,’’ Daniel said. ‘‘I fully believe our defense is the best defense in the league. I go against them on scout team every week during the season. Sometimes our defense will make us look so bad [that] you just have to [remind yourself]: ‘We’re going against the best defense; we don’t stink. We’re executing just fine, they’re just really good.’ That’s definitely a thing.’’

Trubisky is a believer in that narrative.

‘‘Going against our defense every day, it’s not tackle, but we’re seeing a bunch of crazy looks,’’ he said. ‘‘They’re going hard. They’re making it very tough on us. Iron sharpens iron.’’

That mantra is the essence of what this Bears team is all about. For years, the Bears have been one-sided — often much stronger on one side of the ball than the other. Now, with an offense that was 11th in points last season, they think they have a balance in which each side makes the other better.

‘‘I definitely think going against that talent caliber of a defense has made us a lot better offense,’’ Trubisky said. ‘‘We always have to be on top of our game as far as calls with our routes [and] me with my timing and ball placement because you don’t have much time to throw in the pocket against our defense and the windows are going to be very small. So I think that’s helped us evolve as an offense and me as a quarterback.’’

That sounds logical, but it remains to be seen how real it is in practice. Since the opening days of camp, the question has been: Is the defense making the offense look bad, or is the offense making the defense look good? Finally, the time has come for Trubisky and the Bears to answer that question.