The shine has officially worn off.

On Thursday, Trevor Siemian and the Broncos offense hit rock bottom, and he didn’t even toss an interception; maybe the only positive from the night.

Punt. Punt. Field goal. Punt. Half. Punt. Fumble. Punt. Missed goal. Safety.

That’s 10 drives, three points, five punts and three three-and-outs. Oh, and it’s important to mention that the lone field-goal drive came after a Chargers’ muffed punt that placed the Broncos inside the 15-yard line.

Even with Donald Stephenson and Virgil Green back from injury, the offensive line play was miserable, and when they did provide Siemian enough time in the pocket, the Broncos still only seemed capable of check-downs.

Some began to question what exactly the Broncos’ game plan was.

And even when the offense did begin to get things going, they shot themselves in the foot over and over and over again.

After a quick first down on the Broncos’ second drive of the third quarter, Siemian hit Jordan Taylor over the middle for what looked to be a short reception, and “Sunshine” coughed up the ball.

The Chargers recovered the ball on the Broncos’ 36-yard line and promptly put three points on the board.

Two drives later, the Broncos moved the ball into Chargers territory, only for Demaryius Thomas to drop an easy reception, forcing the Broncos to attempt a 56-yard field goal that Brandon McManus would miss.

But that was just the start. With 12 minutes remaining in the game, the Broncos received the ball down 16 points — a two-score game. Touchdown. Two-point conversion. Touchdown. Two-point conversion. Tie game. A win was still in play.

What’d they do? Holding in the end zone, safety. Three-score game.

It was at that point that all hope seemed lost.

What’s worse, though, is that even then it didn’t stop. Yes, the Broncos were down three scores on the road, but they were playing the San Diego Chargers, a team that lives for giving up fourth-quarter leads.

On the very next play, the post-safety kickoff to the Chargers, another muffed punt gave the Broncos the ball near the 50-yard line, and Denver actually drove the ball down the field for a touchdown — 11-point game.

Even better, the Chargers immediately went three-and-out, giving Denver the ball back with 5:45 remaining.

And, with 4:24 left on the clock, Siemian dumped the ball off to C.J. Anderson, who rumbled his way through San Diego’s defense for a … TOUCHDOWN!

One score game, the defense playing well, the offense getting going. The Broncos were about to deal the Chargers another devastating loss, right?

Wrong …

Russell Okung was called for holding, one of the Broncos’ 12 penalties on the night, and one of the many to nullify a positive offensive play from Denver. In fact, every single Broncos lineman was called for a penalty on Thursday night, and all of them seemed to come after a big C.J. Anderson run or catch.

Two plays later …

And even then, the Broncos almost made it interesting. After the Chargers’ second three-and-out of the fourth quarter, Denver quickly moved down the field for a field goal and recovered the subsequent onside kick.

Unfortunately, with just 27 seconds left in the game, a Hail Mary was Denver’s only shot, and from the Chargers’ 45-yard line, Siemian wasn’t even able to get the ball to the end zone — not ideal.

13-21, ballgame.

Siemian finished the night with 230 yards on 50 attempts, an embarrassingly bad 4.6 yards per attempt. For comparison, Blaine Gabbert currently is worst in the NFL with a 5.93 yards per attempt, over a full yard better than Siemian on Thursday night.

There’s plenty of blame to go around, but the bottom line is that if the Broncos want to contend for another Super Bowl, their offense needs to fix some serious, serious flaws.

Luckily, they have 11 days until the Houston Texans come to town.