"We decided on making Trevor Siemian our quarterback," Joseph said. "Both guys competed hard. Both guys wanted the job. We're pleased with both guys, but overall the operation of the entire offense, decision-making, ball placement, was more consistent with Trevor. That's why he won the job."
Joseph had split work between the two quarterbacks in the offseason program, organized team activities, minicamp and training camp. Siemian and Lynch have each started one preseason game.
Siemian likely closed the deal Saturday night when he came in against the San Francisco 49ers with just over three minutes remaining in the first half and led the Broncos on a seven-play, 53-yard touchdown drive.
In three possessions, Siemian led the Broncos to 10 points, and on his touchdown pass -- a 19-yarder to Jordan Taylor -- Siemian bounced back from having a touchdown nullified by a holding penalty on the previous play.
Asked Monday whether he could be a franchise quarterback for the Broncos, Siemian said he thinks he can be.
"I've got a long ways to go. I know where I can get better," he said. "I also know some of the things I do do well."
Lynch said he was disappointed not to be named the starter.
"I gave it everything I had to go out there and win the job, and at the end of the day the coaches made the decision," Lynch said. "Now, at the point where I'm at, I just have to prepare and be ready."
"Obviously I believe in myself to be the starter, but the coaches made a decision and that's what I'm rolling with," he added.
In what turned out to be the last chance for both quarterbacks to make their case on the field, Lynch finished 9-of-13 for 39 yards in almost a full half of work and was behind center for three short scoring drives that each began in San Francisco territory following a 49ers turnover. Lynch also had 27 yards rushing.
Siemian was 8-of-11 for 93 yards and a touchdown.
"I saw Paxton make some plays with his legs, which he should," Joseph said after the game. "He's an athlete. And Trevor, he was solid. He was Trevor. He made good decisions, his ball placement was on point tonight, he controlled the huddle. So I was pleased with Trevor."
In two preseason games, Siemian is 14-of-18 for 144 yards and the touchdown pass for a 118.5 passer rating. Lynch is 15-of-22 for 81 yards with zero touchdowns and a passer rating of 74.2.
Siemian showed a greater comfort level in the Broncos' new offense throughout the offseason. After a slow start in the first few days of training camp, he consistently moved the team in practice and showed "the timing and ball placement" Joseph has said would be important factors in the decision.
The Broncos' decision in 2017 came slightly sooner as compared to when former coach Gary Kubiak awarded Siemian the job over Mark Sanchez and Lynch last summer. Kubiak formally named Siemian the starter the Monday after the team's third preseason game, when Siemian finished 10-of-17 for 122 yards and a touchdown against the Los Angeles Rams.
Siemian, who played most of last season with a left (non-throwing) shoulder injury that required surgery, finished 8-6 as a starter in 2016. He threw for 3,401 yards to go with 18 touchdowns and 10 interceptions.
He had 312 passing yards and four touchdowns in a Week 3 win at Cincinnati and a 368-yard day with three touchdowns against the Chiefs in a game the Broncos lost in overtime. Siemian also threw for 334 yards against the Tennessee Titans.
"I think I just worried about myself and improving," Siemian said of winning a second quarterback competition. "I got a shot coming, and for me, that's all I needed. I think I've grown a lot as a player."
Siemian, a seventh-round pick by the Broncos in 2015, has routinely said spending his rookie year with Peyton Manning and his work as the Broncos' No. 2 quarterback during that season's Super Bowl run was something that has helped over the past two quarterback competitions.
Lynch was a first-round pick in 2016. The Broncos saw improvement from him in the new offense, but consistency and the ability to rebound quickly from mistakes are things he will have to address.
"He knows he's one play from playing, so he can't lose his enthusiasm for getting better as a quarterback," Joseph said Monday. "That's a big deal for him, just keep his focus, be a good teammate and keep working."