Kiszla: Whether Broncos can be NFL’s best defense depends on tricky question linebacker Bradley Chubb has yet to answer

The Astronaut is the X-factor.

For the Broncos to be truly dominant on defense, they need outside linebacker Bradley Chubb wreaking havoc in the pass rush from Week 1. We know Chubb possesses the skills to do it. But in this violent sport, where is the Astronaut’s mindset after missing 12 games in 2019, when a cornerstone of Denver’s defense tore the ACL in his left knee on the last Sunday of September?

“Chubb, we have to get him going. That, I think, will take some time. But we know what he can do,”  football operations chief John Elway said Saturday.

During a year in which COVID-19 has altered how we all go about our business, the pandemic has added a layer of uncertainty to Chubb’s recovery from a serious injury.

This has been a training camp unlike any we’ve seen, as NFL teams have placed emphasis on player health over preparation for the season. After an August in which the preseason schedule was canceled, how much confidence can Chubb really have in his surgically repaired knee, until he takes that first big hit at full speed against the Tennessee Titans?

Learning to fully trust the knee probably will require more than one snap. It might take more than a month. And how long before he’s the Astronaut again will go a long way to determining how good Denver’s defense can be.

Modern sports medicine can make Chubb’s knee as good as new. But it’s not unusual for the recovery process from ACL surgery to require more than 12 months, especially in a player like Chubb, whose explosive burst is among more dangerous items found on his pass-rushing menu of attack.

I asked Broncos coach Vic Fangio: Will Chubb be on a “pitch count” that limits his snaps early in the regular season?

“He may be on one. He may not be. We’re going to see how he does. He’s not 100 percent yet,” Fangio said.

“There’s a lot to overcome when you’re dealing with an ACL injury that he’s had, particularly the position he plays, where he’s leaning on people a lot and taking on the offensive linemen. It could be a pitch count, but I don’t think it’s a conditioning pitch count. We’ll just see how it goes.”

How slow will the Broncos go with Chubb? It could reveal much about whether protecting Chubb’s long-term health needs to take priority over Fangio’s natural desire to get the Broncos off to a fast start in his second season as coach.

As a rookie in 2018, Chubb played 844 snaps. He was on the field for 78.4% of Denver’s defensive plays, evidence that reveals how integral the Broncos viewed their young linebacker to the team’s success.

One of the more interesting mysteries as the Broncos head toward their home opener on Sept. 14 revolves around how much Chubb will play. Will he be on the field 50% of the time? I’d be pleasantly surprised if it’s more.

And nobody would be shocked if Denver decides it’s wiser to break Chubb in cautiously, as a situational pass-rusher when the Titans are likely to throw the football.

For all the X’s and O’s and video analysis in pro football, sometimes coaching is more about pure gut instinct than 21st century science.

The Broncos’ early schedule allows the team no time to ease into the season, with four games that will go a long way to determining whether they should be taken seriously as a playoff contender.

Denver opens at home as slim 1.5-point favorites against Derrick Henry and the rush-heavy Titans in a game that feels like a toss-up in no small measure because no fans will be allowed in Empower Field at Mile High as a safety precaution in these pandemic times.

And the road rises steeply uphill from a season opener whose final play won’t be until nearly midnight. There’s a trip to Pittsburgh, where Ben Roethlisberger will be intent on proving he’s not washed up, on a short week that will test Chubb’s powers of recovery.

On the last Sunday of September, how much can Chubb hassle our old pal Tom Brady, wearing his new Tampa Bay Bucs uniform? The fourth stop in the opening stretch will present another short week for Chubb, with a Thursday night tilt at the Jets, where the Broncos need to steal a road victory.

“We should be the best defense in the league, no question,” defensive end Shelby Harris said during camp.

The best? While I admire Harris’ lofty ambition, Super Bowl 50 was a long time ago.

Fangio was hired to do a rebuilding project that took that championship defense down to the foundation and studs. Compared to his first game as coach in 2019, there will be no fewer than five new starters on the defensive side of the ball when the Broncos take the field against Tennessee.

A dominant Denver defense would hide many of the inevitable growing pains for young quarterback Drew Lock. But how soon will this Denver defense be able to make Brady feel old and Patrick Mahomes feel mortal?

Not until Chubb again feels like his dominant self, and the Astronaut takes flight.