Broncos safety Kareem Jackson’s two-game suspension to end the year has created an opportunity for second-year player Trey Marshall.

Before practice on Wednesday, coach Vic Fangio said Marshall will start Sunday against Detroit, allowing the Broncos to keep Will Parks in his nickel back role. Duke Dawson will play in six-defensive back personnel.

Jackson was suspended by the NFL on Tuesday for violating the league’s Policy and Program on Substances of Abuse stemming from his Sept. 19 DUI arrest.

“Obviously, we’re disappointed,” Fangio said. “I just emphasized to (the players) to learn from others’ mistakes and learn from Kareem’s mistake. It was a one-time thing and we don’t anticipate it happening again, but those one-time things can come back and bite you.”

Marshall, an undrafted free agent in 2018 from Florida State, has played only 37 snaps of defense this year (three tackles).

“I didn’t really play a lot last year so getting these limited reps this year have helped,” Marshall said.

Marshall said what he learned most from Jackson was “just different things, but really, just the way he practices.”

Said safety Justin Simmons: “I think Trey will be fine. He’s been locked in since Week 1 and really knows the system well. He knows he’ll be out there with a bunch of guys who will be helping him along the way.”

Injury updates. Right guard Ron Leary (concussion), right tackle Ja’Wuan James (knee), left guard Dalton Risner (illness) and defensive end DeMarcus Walker (ankle) did not practice Wednesday.

Fangio said Leary is still having “difficulties” with his concussion and is expected to miss a third consecutive game and James “probably won’t play either.”

If Walker isn’t active, Jonathan Harris would likely play again after making his Broncos debut against Kansas City (36 of 68 snaps and four tackles).

“I had some good plays and a few plays where I needed to do better, but definitely something to build on,” Harris said. “I knew I had to play with my technique because when you get out of that framework, it will hurt you.”

Lions’ open letter. Despite a 3-10-1 record (seven consecutive losses) and a 9-20-1 record since the start of last year, Detroit ownership announced this week that general manager Bob Quinn and coach Matt Patricia will return in 2020. Related Articles Broncos Journal: Helping offensive line against Tampa Bay could take on many forms

Broncos Insider: Why it’s a bad idea for fans to root for Denver to tank for Trevor Lawrence

Kiszla: At this point in storied NFL career, is old Tom Brady any better than Broncos journeyman Jeff Driskel?

Jackson: Broncos tight end Noah Fant knows how to dance. Now he needs to learn how to get dirty

Broncos Briefs: Phillip Lindsay doubtful to play Sunday, but progressing from toe injury

“To be clear, our expectation is for the Lions to be a playoff contender in 2020,” owner Martha Firestone Ford, vice chair Sheila Ford Hamp and president Rod Wood said in a letter to Lions fans posted on the team website Wednesday.

Like the Broncos, Detroit is on its third quarterback of the year (rookie David Blough) following injuries to Matthew Stafford and Jeff Driskel.

According to the Lions, they led in each of their first 12 games but went 3-8-1. Last week against Tampa Bay (a 38-17 loss), Detroit was outgained 314-2 at one point.

Footnotes. Although his batted pass against Kansas City was negated by penalty, Broncos defensive end Shelby Harris still leads all NFL defensive linemen (seven) this year and his 14 since the start of 2017 are fifth-most. … The Broncos’ rush defense has fallen from 11th (100.5 yards per game) entering the Minnesota game to 20th (113.6). … Entering the final two games, the Broncos have 83 “explosive” plays (rush of at least 12 yards/catch of at least 16) — 63 passes and 20 rushes. Opponents have 93 explosive plays (65 pass/28 rush). … The Broncos will wear their color-rush uniform (dark blue helmets, orange jerseys and orange trousers) against Detroit.