Unique schedule.

The Broncos will open their season Monday with a very thin defensive line.

Starting defensive end Jared Crick (back) and reserve Zach Kerr (knee) were ruled out against the Chargers, and reserve nose tackle Kyle Peko, who was working his way back from a foot injury, was waived. The Broncos are expected to make a corresponding roster move to fill Peko’s spot before the game.

Kerr and Crick had been listed as day to day, but they were absent from Friday’s practice and the team’s Saturday morning walkthrough session.

Kerr has not practiced since injuring his knee in the team’s third preseason game against Green Bay on Aug. 26. Crick suffered what coach Vance Joseph said were back spasms during training camp and did not play in the team’s last three preseason games.

“I think Jared is getting better, but he’s not well enough to play a football game right now,” Joseph said. “And in our opinion, if we put him out there this week, which we could probably, it would hurt us moving down the road.”

Adam Gotsis will start in place of Crick opposite Derek Wolfe on the defensive line, which leaves Shelby Harris as the team’s lone backup at end.

Peko recently returned to practice after recovering from surgery to repair a fracture in his foot, which he suffered earlier in the offseason.

“Kyle Peko has gotten better fast,” Joseph said. “He practiced the last two days and he looked OK.”

Running back Devontae Booker (wrist) and quarterback Paxton Lynch (shoulder) also were officially ruled out, although they weren’t expected to play Monday. Booker is inching closer to a return from wrist surgery, but there is no set timetable on when he will suit up in the regular season. Lynch is projected to miss at least the first few weeks of the season to recover from a sprain to his throwing (right) shoulder.

Joseph, a first-year head coach, has adopted a practice schedule different from what the Broncos are accustomed to in recent years. It’s a regimen used by Marvin Lewis in Cincinnati, where Joseph was the defensive backs coach from 2014-15.

After their first two days of practice each week, the Broncos will use the third day as a “mental practice” and the fourth as more of an up-tempo workout.

“The reason you do it is you want two recovery days versus one,” Joseph explained. “So we do more work on Wednesday and Thursday, and take Friday as a mental practice and a recovery day for the players. But it’s not a loss when you’re talking about football. The offense got 85 reps today (during walkthrough), so that’s a practice and a half for us. Defensively we got 65 reps. So we’re not losing our game plan knowledge, but we’re gaining, in my opinion, a day of recovery for our players. It’s a long season, so we want to make a point to start recovery now and not at Week 10.”

Footnotes. Veteran running back Jamaal Charles practiced in full again Saturday and “is ready to go,” Joseph said. … Because the Broncos will have a shorter week after their Monday night opener against the Chargers, the team has already started to prepare for their Week 2 meeting with the Cowboys. … Receiver Cody Latimer will be the Broncos’ kickoff returner Monday night.