"We've been saying it for a long time, we said it last year. Him seeing the way it's done, he just has that Peyton Manning vibe—he kind of looks like Peyton Manning too. It's great to have that energy from Trevor in the locker room and on the football field. I trust him in everything, our whole organization trusts him. He's looking 10 times better than he did last year, and he did a lot of great stuff for us last year."
The former seventh-round pick beat out 2016 first-round pick Paxton Lynch for the starting job.
Siemian appeared in 14 games for the Broncos last season, throwing for 3,401 yards and 18 touchdowns. While his 8-6 record seems good for a first-year starter, it was a disappointment for a team that won the Super Bowl the year before.
Miller and the rest of the Denver defense have seen a wide range of quarterback play over the past few seasons. Manning had one of the best years in NFL history in 2013, throwing 55 touchdowns while leading the highest-scoring offense ever. However, the future Hall of Famer struggled in 2015, allowing Brock Osweiler to earn some starts.
There were also plenty of question marks last year between Siemian and Lynch, enough for Denver to bring back Osweiler on Monday after he was released by the Cleveland Browns.
Still, Miller's confidence in the starter can only be a positive heading into the 2017 season.
Per OddsShark, the Broncos are listed as 7-2 underdogs to win the AFC West, behind both the Oakland Raiders and Kansas City Chiefs. If Siemian approximates Manning's play in any fashion, though, this team could be a Super Bowl contender once again.