ENGLEWOOD, Colo. -- The Denver Broncos' starting offense, the one loaded with Pro Bowl players at skill positions and a future Hall of Famer at quarterback, is done for the preseason.

The regulars, like quarterback Peyton Manning, wide receiver Demaryius Thomas, running back C.J. Anderson and guard Louis Vasquez -- all have appeared in the Pro Bowl over the past two seasons -- will not play in Thursday night’s preseason finale. Overall, the Broncos have taken a safety-first approach with the group and limited their snaps -- Manning played just 63 in two games -- while wide receiver Emmanuel Sanders did not appear in any of the first three preseason games because he was recovering from a hamstring injury.

In the end, though, the Broncos’ starting offense did not construct a touchdown drive in any of the first three preseason games. Yes, Brock Osweiler threw a scoring pass to tight end Virgil Green late in the first half of the preseason opener in Seattle, but that wasn’t the starting offense on the field. Saturday night against the San Francisco 49ers, the starters' work resulted in two punts, two field goals and a Manning interception.

“We wanted more points than we scored,’’ tight end Owen Daniels said . “ ... We’ve got to clean some things up, down in the red zone, obviously, but we feel good about moving the ball. So we’ll continue to work these next two weeks and get everything ready to go.’’

And one thing the Broncos have done with Manning at quarterback over the past three seasons is score points. They were second in the league in scoring in both 2012 (481 points) and 2014 (482 points) to go with the NFL’s single-season scoring record in 2013 with 606 points, also the first time any NFL team crossed the 600-point barrier.

In all, the Broncos have averaged 32.7 points per game in Manning’s three regular seasons with the team, 34.0 points per game over the past two seasons. So, the preseason drought has raised eyebrows on the heels of the arrival of a new playbook.

Executive vice president of football operations/general manager John Elway has called the offense “a work in progress’’ and after Saturday night’s game Manning said: “We’re still very much figuring out who we are and what we’re going to be.’’

Saturday night the Broncos had a 13-play drive to go with a 14-play drive in the starters’ half of work. Both of those drives ended in field goals.

“[It’s] super frustrating, you go out there and you put a good drive together and you move the ball well, and we're just not finishing. ... We'll definitely be finishing Week 1, I can promise you that.”

The Broncos also followed a safety by its defense -- DeMarcus Ware tackled 49ers quarterback Colin Kaepernick in the end zone early in the second quarter -- with a mistake of its own. In just the kind of situation the Broncos have said they want to thrive in this season, when the defense forces the issue and gives the offense a short field, the Broncos didn’t cash in. On a drive that started on the 49ers’ 48-yard line following the return of the free kick, the Broncos moved to the 49ers’ 19 before Manning threw an interception in the end zone on an underthrown ball to Thomas.

Also, on the Broncos' second field goal drive of the first half, they were unable to convert after having a first-and-goal from the 49ers’ 5-yard line. On third-and-goal from the 3, Manning didn’t see a wide-open Daniels in the end zone as the 49ers sent a heavy blitz at him and couldn’t squeeze the ball in to Cody Latimer.

“They brought everybody on the play, matter of fact nobody was even covering Owen on the play,’’ Manning said. “I wish I would have looked there, but I was kind of keyed in one going to Cody, giving him a chance to make a play.’’

The Broncos have changed their personality at least some with a defense that is expected to be one of the most aggressive in the league to go with a pumped-up run game. That hasn’t been the team’s formula over three high-scoring seasons that have each ended in playoff disappointment.

Still, the opener is two weeks away and the Broncos are on the hunt for some more touchdowns. That’s because, in short, they’re going to need them.

“I feel pretty confident from a coaching standpoint we can go fix those things,’’ coach Gary Kubiak said. “We're going to continue to do a lot of things offensively and we just have to do some of them a lot better than we did [Saturday].”