JACKSONVILLE – Senior writer John Oehser examines what we learned from the Jaguars' 40-26 loss to the Kansas City Chiefs Sunday in the 2019 regular-season opener at TIAA Bank Field …

1.Foles is out for a while … That's the major news from Sunday, with new Jaguars starting quarterback Nick Foles sustaining a broken left clavicle late in the first quarter of his first game with the franchise. That's a major blow. There's no way around that.

2…. Gardner Minshew II is the Jaguars' starting quarterback … The sixth-round rookie played three quarters in place of Foles Sunday, completing a remarkable 22 of 25 passes for 275 yards and two touchdowns. He got extensive preseason playing time, developing rapidly during that time.

3. … and he's better than many thought … Remember the preseason? When many wondered if Minshew was the right guy to be the backup? Considering the up-and-down – mostly down – preseason offensive performance, that was a fair question. But Minshew showed poise, accuracy and awareness Sunday. Time will tell how he fares as a starter, but you couldn't have asked for much more from a backup quarterback.

4. … but the Jaguars' task just got tougher. Make no mistake about this: While Minshew played well Sunday, the season just got a world tougher. There are cases in NFL history of starting quarterbacks missing large swaths of time and their teams responding by playing well. Foles' last team, the Philadelphia Eagles, come to mind. Foles replaced starter Carson Wentz in 2017 and led the Eagles to a Super Bowl victory. But those situations are rare. History and logic are against the Jaguars now. We'll see if they can win the matchup.

5.Marrone was impressed with Minshew's performance Sunday … Jaguars Head Coach Doug Marrone is up front when dealings with media. Marrone didn't gush when discussing Minshew Sunday, but he did say this: "I feel better about him now, today, after Week 1 than I did probably during the preseason." Marrone values regular-season performance; Minshew performed well Sunday. That's encouraging.

6. … and so were his teammates. Wide receiver DJ Chark Jr. on Minshew: "He's fearless and that's the thing that I like about him the most. He steps up in the situation, he won't blink. … If he wants to change the plays, whatever he wants to do, that's what we're going to do and we're going to make it work."

7.This defense is not elite. Not yet, anyway. Elite defenses don't allow nearly 500 yards and allow receivers to run wide open all over the field the entire first half. There is talent on this Jaguars defense. A lot of it. And the Chiefs' are phenomenally good offensively. But if the Jaguars are going to be elite, they must look more intimidating – and more prepared – than they did Sunday.

8.The defense missed Marcell Dareus. The defensive tackle, an underrated force in the middle, missed the opener with an elbow injury. In his absence, end Calais Campbell kicked inside in base situations and played more than is ideal (81 percent of the snaps).

9.The tackles were ready for their debut. Much pregame focus was on Jaguars offensive tackles Jawaan Taylor and Will Richardson. Both were making their NFL debuts. Taylor was a rookie starting at right tackle, and Richardson – a second-year veteran – was kicking outside to start at left tackle after competing at right guard position through training camp. Though Richardson was called for one holding penalty and Taylor was called for two, both appeared to perform admirably. "I thought they did a nice job," Marrone said. "They really did."

10.The discipline issues remain real. This wasn't just linebacker Myles Jack getting ejected for fighting, then having to be held back from the Kansas City bench afterward. Safety Ronnie Harrison was called for taunting later in the game – with the Jaguars' defense having been dominated much of the game. "In the heat of the battle, when that stuff happens, it takes a lot and we ask our players to withhold themselves and show that composure and that's what we're looking for," Marrone said. "We'll keep preaching it, and I believe that we'll get it. I think our players understand that. We've got to keep doing it and keep preaching it." Coaches will get blamed for this, and that's fine: it's ultimately the head coach's responsibility. But players simply must stop this behavior. It's not as if every player on every team gets called for this. Just stop.

11. Chark looks like he's taking a step. There were multiple reasons for optimism offensively Sunday, but Chark stood out. The Jaguars need the 2018 second-round selection to take a second-year jump. Four receptions for 146 yards and a touchdown is a good first step.

12.Quincy Williams is healthy … The rookie outside linebacker said he felt the aftereffects of a preseason meniscus injury, but he started Sunday and played 66 percent of the defensive snaps. He also showed his quickness and good awareness. It was a good start.

13. … and so is Marqise Lee. The sixth-year veteran wide receiver played 12 snaps in the regular-season opener, which was about as planned after he missed last season with multiple torn knee ligaments. "I think I did pretty good," he said. "I didn't get too many opportunities, but just for the fact that I had an opportunity to be out there and get my feet wet was more important than anything. No complaints."

14.The players are resolved. Players and coaches said the right things after Sunday's game, and sounded resolved not to let one bad loss turn into a bad season. The consensus was that a lesson was learned from last season. "Last year, we had a struggle with it," Lee said. "This year, we have an opportunity to comeback and show we can get over it." Stay tuned.