KUSA—It hasn’t been the smoothest of offseasons for the Denver Broncos.

It began with head coach Gary Kubiak resigning for health reasons. He was replaced not by Kyle Shanahan, son of Mike Shanahan, the best head coach in Broncos’ history, but Vance Joseph, a one-year defensive coordinator.

It moved on to The Great Quarterback Competition where seventh-round pick Trevor Siemian beat out first-rounder Paxton Lynch for the second year in a row.

It finished with the controversial release of Pro Bowl strong safety T.J. Ward, the roster cut of preseason rookie standout Kyle Sloter and return of Brock Osweiler.

The Broncos can calm the waters by defeating the Los Angeles Chargers in their season opener tonight (8:20 p.m. kickoff, Channel 20). Here are 9 key factors for the Broncos tonight:

1.Pressure Philip

Give Chargers’ quarterback Philip Rivers time to throw and he is one of the NFL’s best pure passers. He is 12th all-time in passing yards (45,833) and 8th in touchdowns (314). But while all quarterbacks are less effective when pressured in the pocket, Rivers really suffers because of his immobility. The Broncos’ 57 sacks against him are more than any other team. Von Miller has 13.5 of those sacks, putting Rivers No. 1 on his list.

Establishing a consistent pass rush is one of the Broncos’ concerns entering this season because of the retirement of DeMarcus Ware and injury to Shane Ray at the outside linebacker position opposite Miller. The return of Shaq Barrett from an offseason hip injury should help.

2.Play it cool, Trevor

Even if Trevor Siemian played better than expectations last season, the seventh-month, Great Quarterback Competition this offseason could have been taken as a sign his bosses didn’t think it was good enough.

Siemian didn’t take it that way, and his ever-unflappable demeanor is one reason he keeps winning the job. But he needs to have a strong opener to quash any concerns of the Broncos’ fan base, not to mention his superiors.

3. Stop Melvin Gordon

To think the Broncos nearly signed Calais Campbell, who just surpassed J.J. Watt as the NFL’s best 3-4 defensive end with his 4.0 sack performance in Jacksonville’s stunning season-opening win at Houston. Instead, the Broncos’ top defensive ends opposite Derek Wolfe are both hurt (Jared Crick, Zach Kerr) and won’t play.

Shelby Harris and Adam Gotsis will get the playing time against the Chargers, while the Broncos may also call up nose tackle Tyrique Jarrett from the practice squad to spell starter Domata Peko.

Gordon, a first-round draft pick out of Wisconsin in 2015, was a fumbler as a rookie, but improved dramatically in his second season, rushing for 997 yards and 10 touchdowns at halftime of his 13th game when a knee injury that required surgery ended his season.

4. Blockin’ Bolles

The Broncos have a rookie left tackle in first-round pick Garett Bolles and the Chargers are sure to test him, not only one-on-one with Melvin Ingram, who combined for 18.5 sacks the past two years, and Joey Bosa, who had 10.5 sacks in 12 games as a rookie, but through blitzes and disguised blitz looks.

5. Get C.J. and Jamaal going

C.J. Anderson will be the Broncos’ starting tailback for a third consecutive season. He will need a few carries to find his tackle-breaking rhythm. Jamaal Charles has been kept fresh through the offseason and preseason in hopes he will breakout his burst and instincts tonight. Given Charles has played little the previous two seasons because of a knee injury, he may be limited to 10 touches or so.

6. Get Demaryius and Emmanuel involved

This is the Broncos’ 1,000-yard receiving duo three years catching. The return of the screen and run for Demaryius Thomas would be an especially nice touch.

7. Kickin’ McManus

This game could easily come down to a field goal. Chargers’ rookie Younghoe Koo made a 27-yard field goal and 33-yard extra point during the preseason. And that was it. He can be tricky on onside kicks but the only trick that matters on game day is consistently splitting the uprights with the pressure on. The Broncos’ Brandon McManus was 10 of 10 in field goals, 3 of 3 in extra points, during the team’s 2015 postseason run to Super Bowl 50. He was 10 of 10 in field goals and 11 of 11 in extra points during the preseason.

8. Turnover ratio

Gordon and Rivers are known fumblers. Rivers has also averaged better than an interception a game the past three seasons.

Siemian only threw 10 picks in 14 games last year but he figures to push the ball downfield more in his second season.

9. No Antonio record on home turf

The Chargers have consistently been the most lethal tight end team of the past 15 years. So much so Antonio Gates is tied with Tony Gonzalez for the all-time lead in touchdown catches among tight ends with 111. He has 11 against the Broncos, who are third behind his 16 scores against Kansas City and 13 against Oakland.

Gates’ tight end partner, Hunter Henry, had his best rookie game against the Broncos last season when he had six catches for 83 yards and a touchdown in a 21-13 win at San Diego.

Justin Simmons, the second-year safety who replaced Ward, will have his coverage skills tested quickly.