Mark Sanchez, Trevor Siemian show they were busy during Broncos' 'off' time

ENGLEWOOD, Colo. -- Denver Broncos coach Gary Kubiak said he was interested in how quarterbacks Mark Sanchez and Trevor Siemian would look Thursday at their first training camp practice in preparation for the 2016 regular season.

Kubiak got his answer as Sanchez and Siemian opened the competition for the starting job with gusto. Each showed he'd put in more than a little work after the team closed its offseason program last month.

"I saw good things, I thought Mark was very sharp in practice ... just looked confident," Kubiak said. "Our guys came back good."

Until Kubiak picks a starting quarterback, the Broncos' training camp and preseason could have a Groundhog Day feel to it, with much-repeated questions about who's ahead, who's winning and how they have looked. Kubiak stuck to his plan Thursday in the opening practice of training camp with the work divided equally among Sanchez, Siemian and rookie Paxton Lynch, with Sanchez getting the first crack at running the offense with the starters.

However, it was clear both Sanchez and Siemian were busy during the "off" time between the end of the offseason program in June and Thursday's practice. Both were efficient and comfortable in the offense -- Sanchez in particular drew praise from Kubiak.

Kubiak had openly wondered earlier in the week how Sanchez and Siemian would look when they returned to the field. Lynch already had showed Kubiak some progress in the rookies-only workouts Monday, Tuesday and Wednesday.

But Thursday, Sanchez and Siemian each showed he was ready to state his case for the starting job.

"Smart players know exactly what's coming the first day," Kubiak said. "They've looked at scripts, they know what's going on in practice and you can see the difference in their preparation. All of a sudden, a young kid comes out here and his mind starts wandering. A lot of people out here watching them and they get a little stage fright, so to speak, but our guys came back good. I liked the way they bounced around."

Siemian said he threw to receivers at Northwestern during the time away. When asked Thursday what he thought would separate the eventual starter at quarterback from the others, he offered an answer that closely resembled the job description Kubiak has in mind.

"I think the quarterback's got to be able to lead, he's got to be able to operate and take care of the football, especially with the team we've got," Siemian said.

Sanchez, who brought a group of Broncos, including the team's receivers and Siemian, to Los Angeles early in the offseason, said Thursday he was able to have some additional throwing sessions with some of the receivers and tight ends in recent days as well as at another session in Los Angeles.

"I think that we have great chemistry," Sanchez said. "And we just have to continue working at it."

Lynch has shown improvement, especially in his footwork, since he returned for the start of training camp. But Thursday the rookie was slightly erratic at times with his throws as it looked as if the adrenaline of the moment was affecting him.

Lynch is in the mix, but either Sanchez or Siemian is the team's likely starter Sept. 8 when the Broncos and Carolina Panthers open the NFL's schedule with a Thursday night game. And some of that has to do with experience, 72 regular-season starts for Sanchez and one year in the School of Manning for Siemian, but some of it was also proof that Sanchez and Siemian had each kept his word over the last month.

Both quarterbacks had said, as the Broncos adjourned their offseason program, they wouldn't take much of a break with the prospect of the competition for the starting job an enticing carrot for both to keep working. And Sanchez said Thursday all three quarterbacks really are all in it together even though only one will be selected.

"It's a competitive atmosphere ... there's no shying away from helping a guy, at least in my opinion," Sanchez said. "I have no problem imparting any kind of wisdom or a situation that I've been in, if I can help one of the other guys, I have no problem with that. The best player will play and we're just going to try and help this team."