ENGLEWOOD, Colo. — As Trevor Siemian approached his second season as a starter, he spent most of his time focused on the Los Angeles Chargers ahead of the team's opener.

But he also evaluated nearly a dozen quarterbacks across the league as he looked to improve his own game.

"I'll just look at other quarterbacks," Siemian said. "[I] take a look at what they do well, and there's so many guys around the league that do a lot of different things well, so [I] just kind of see why they're good and what makes them good. [I] see what works."

One of those players will be on the opposing sideline this weekend when the Dallas Cowboys head to Denver.

Quarterback Dak Prescott finished his first season with a 67.8 percent completion percentage, 3,667 yards, 23 touchdowns and just four interceptions. He also added six rushing touchdowns.

He replicated the same sort of execution Sunday night against the Giants, as he finished 24-of-39 for 268 yards and a touchdown.

When Siemian watches Prescott, he sees someone who in no way looks like a second-year player.

"I love watching Dak," Siemian said. "He's so impressive, right? To me, it looks like he's been playing for 10 years. This is his second year — it looks like it's Year 12 for him. He sees things really well. He's really confident in their scheme. He's impressive."

In particular, Prescott manages the offense with the poise of a much older player.

"He's in ultimate control of their offense," Siemian said. "You see him on the ball a ton. Obviously, very accurate. He's got good chemistry with those receivers. I feel like they're always in sync.

"They have a really good rhythm to their offense. I think that's No. 4's job."

No. 13 studied No. 4 in the offseason. Come Sunday, he'll share the field him.