Trevor Siemian

He's 1-0, but Denver Broncos quarterback Trevor Siemian still has a lot to prove

Published Nov. 15, 2016 2:20 p.m. ET

Dieter Kurtenbach

Trevor Siemian is undefeated as an NFL quarterback.

The former 7th round draft pick out of Northwestern, whose senior season saw him throw for 7 touchdowns and 11 interceptions, led the defending Denver Broncos to an impressive 21-20 win over the Carolina Panthers in a rematch of Super Bowl 50 Thursday night, opening the 2016 NFL season.

Siemian performed admirably, considering the stage and his level of experience — he had taken only one regular-season snap in the NFL, a kneel down, before Thursday’s game — as he completed 18-of-26 passed for 178 yards. He threw for a touchdown but also two interceptions.

The Broncos didn’t win the game because of Siemian — thank the Denver defense, poor Carolina clock management, a dazed Cam Newton, and a missed field goal with four seconds left for that victory — but you could argue that he didn’t put Denver in a position to lose, either.

Siemian was shaky late. Siemian’s inexperience was on full display in the fourth quarter, when, after he dumped the ball to CJ Anderson for a 25-yard touchdown “pass”, he went 1-for-4 for a total of six yards.

He missed open receivers that could have put the game away earlier...

…and failed to do the little things that only coaches seem to notice.

It was the 24-year-old’s first game, though — cut him some slack, right? Well, Siemian showed off his quick release and tremendous accuracy on short passes, and many will give him credit for doing that against Carolina’s defense, which was one of the best in the NFL last year.

But that was last year, and if we’re talking about the Carolina front-seven, it still deserves praise. Despite a great game from Denver's improved offensive line, there was pressure on the pass rush, and Siemian handled that well for most of the game. But the Panthers' inexperienced and mediocre-at-best secondary was wildly susceptible to big plays Thursday — big plays Siemian didn't show that he had the arm strength to make. He didn't complete a pass of over 20 yards downfield Thursday and the tape will show that the Broncos left points on the field with their quarterback play.

Better defenses will be able to funnel the Denver passing offense outside by stacking nine men in the middle of the field — daring Siemian to throw outside the numbers on the field. Can he make those throws — the ones that are requisite for an NFL quarterback? We know Paxton Lynch can — the kid has arm talent for days.

Siemian will grow with time on the field, but Thursday showed that he will have to adjust to keep his starting job. At the same time, NFL defenses are going to adjust to him now that he has game tape. Which do you think will adapt faster?