ENGLEWOOD, Colo. --You're not going to answer questions on the first day of organized team activities. But you can begin laying the groundwork for those answers, particularly on the melding of offensive philosophies, the search for depth all around the roster and the composition of the first-team offensive line.

"This is the time to work and experiment," quarterback Peyton Manning said.

What the Broncos wanted from the first OTA of the Gary Kubiak era was intensity and vigorous effort -- within the constraints of offseason Phase 3, which forbid live contact and the wearing of shells or pads. But players can wear helmets, and team offense-vs.-defense drills are permitted.

"I thought it was a really good first day, and got a lot of reps in," Head Coach Gary Kubiak said. "We need to have a good month."

And the urgency is there because all three phases have plenty to absorb. There were plenty of takeaways from the day's work, including:

1. EMPHASIZING THE WORK UNDER CENTER.

Everyone with even a passing interest in the NFL or the Broncos of recent years knows how proficient Manning is when he works in the shotgun, in an up-tempo attack. That's why the bulk of Manning's work Wednesday -- and for the practices that follow -- involved lining up under center.

"That's kind of the plan. We're going to do that initially," Kubiak said. "We know the other end of the stick (shotgun) is fine; that's something that he's been doing forever. So we're going to spend a lot of time under center initially in our process and how we're going to go about our teaching.

"We have a nine-day installation period that we have, so he's going to be under [center] for a good three days before we move back, but he's been very responsive, and he's working extremely hard."

"We have done a lot of that during Phase 2 and Phase 3," Manning said. "Whatever they ask me to do, I feel like I can do it."

It wasn't always elegant; Manning hit the ground after taking a snap under center midway through practice; Von Miller recovered the subsequent fumble.

"I don't remember that happening," Manning quipped, joking that video director Steve Boxer might have erased the film from the internal archives already.

"The one thing the league always wants you to do is to keep players off the ground. So we preach it. We preach it and we gave out t-shirts today (reading), 'Stay on your feet,' and he's the first one to hit the ground," Kubiak said, smiling.

2. DEFENDING WITH ENERGY.

The defense created three takeaways and is "probably even a little ahead" of the offense, Kubiak said.

"I think we're pretty simple on defense," he said. "I think (defensive coordinator) Wade (Phillips) is a great teacher, and there is some crossover from what they've done in the past."

"I liked our defense. It was aggressive; it looked fast, physical, and it looked strong," added linebacker Brandon Marshall, who is watching OTAs from the sideline as he recovers from a foot injury. "I like what I've seen so far."

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3. THE COMPETITION BEGINS UP FRONT.**

Given good health, the Broncos know they will go into the season with their recent All-Pro pillars at left tackle (Ryan Clady) and right guard (Louis Vasquez). Beyond that, it's nothing but question marks, so you can't read too much into who gets how many repetitions on the first team on each day.

Kubiak admitted that he would "love to" know the starting quintet on the offensive line when training camp begins.

"But we're still in a very competitive situation eight or nine deep," Kubiak said. "That's probably a good thing. So we're young, and we've just got to keep going here."

Nothing in regards to the alignment of the offensive line Wednesday was a surprise; Kubiak laid much of it out after the draft, including his note that Michael Schofield would see some work at left tackle behind Ryan Clady. Part of the reason for that was so Schofield could be a "swing tackle" if he didn't earn the starting job at right tackle which Kubiak said would begin with Chris Clark ahead of Ty Sambrailo.

At center, Gino Gradkowski is the experienced option, with a full season as a starter and a full year of practice under Kubiak and Offensive Coordinator Rick Dennison from last year in Baltimore. Wednesday, Gradkowski did well at getting to the second level and springing running backs like C.J. Anderson for solid gains. But it's clear the Broncos are high on 2014 sixth-round pick Matt Paradis -- and what Gradkowski can do for him.

"I also knew he'd be a great teacher for Matt," Kubiak said. "Matt's a young player who's in a competition to be our starting center, and he's not only going to compete against Gino, but Gino's going to help him. That's the type of pro Gino is. I think that's real important."

Kubiak also noted May 2 that Gradkowski would work some days at guard, and the need for "swing players" means that others on the interior will move around, which means that Gradkowski, Paradis, Ben Garland, Shelly Smith and Max Garcia will be busy.

"There will be days when we say, 'OK, Gino, you're going to guard for this practice.' Because those guys will have to swing," Kubiak said then. "Whoever wins the job up front, those other guys will have to be swing players."

4. WORKING WITHOUT ANTONIO SMITH.

In the wake of reports of a criminal investigation into defensive end Antonio Smith, the Broncos opted to excuse him from the voluntary work until his situation is resolved.

"I talked to Antonio late last Wednesday night, and he informed me of what the situation was," Kubiak said, adding that he talked with Smith "numerous times" during Memorial Day weekend and met with Executive Vice President/General Manager John Elway and President/CEO Joe Ellis.

"Bottom line, between us and Antonio, we just felt like the best thing to do was for Antonio to devote all of his energy and time right now to this situation. He agreed with that; we agreed with that. That's how we came to that conclusion."

Kubiak hopes for some clarity regarding the situation in the near future."

"It's our understanding -- I don't know that I'm right -- but it's our understanding that maybe we'll have some answers here in a week or two. I hope that's the case," Kubiak said. "But the most important thing for him right now is to devote all his time and energy toward this situation. So we'll see what happens."

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5. STILL NO DEMARYIUS THOMAS.**

The only other healthy Bronco who did not practice Wednesday was Thomas, whose franchise tender remains unsigned. But Kubiak said he has spoken with the six-year veteran during the offseason.

Kubiak said it has been "a few weeks" since he last spoke with Thomas, but that Wide Receivers Coach Tyke Tolbert has stayed in communication with the three-time Pro Bowl wide receiver "a great deal."

"Obviously, we're talking football, trying to do all we can from that standpoint (so) that when it is time for him to come in, that he's caught up as much as he possibly can be," Kubiak said.

But it's not the same working remotely.

"I'd rather him be here. Y'all know that. He knows that. The players know that," Kubiak said. "So you want everybody here. But you also understand the rules, you understand the situation, you understand what's going on.

"So as a coach I think you've got to deal with what's going on here, and we've got a lot of guys working their tail off, and I'm counting on him taking care of his business. His history says he will do that. He's been a great player and a great person, as well. We're counting on him doing that, and I know his teammates are doing the same."

6. MORE WORK FOR CODY LATIMER.

No one could benefit more from Thomas' absence than Latimer, a seldom-used backup last year, who projects as the Broncos' No. 3 wide receiver but moved up in Thomas' absence.

That provided him plenty of repetitions with Manning during Wednesday's work, and he responded with some nice receptions, including a medium-range slant in which Manning led the second-year pass-catcher perfectly for the grab.

But others made some plays with various quarterbacks,

"There's going to have to be some young receivers (who) really step up, and Cody's one of those guys," Kubiak said. "I think it's a very competitive situation right now.

"But, yes, it's an important month for Cody," Kubiak added a moment later.

Jordan Norwood was back at practice after recovering from a torn anterior cruciate ligament suffered during training camp last August; he figures to be in the mix on punt returns along with several others, as he was last summer. Nathan Palmer, Isaiah Burse and Bennie Fowler are also back for another go-around.

"Bennie Fowler practiced [well] today," Kubiak added. Fowler punctuated his day with a deep reception down the seam from Brock Osweiler during a team period near the end of practice.

"This month's going to help us find out a lot about the youth at that position [wide receiver] on this football team, as well as inside linebacker," Kubiak said. "I want to see who's going to take advantage of it."

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7. MAKING DO WITHOUT THE TOP ILBs.**

Marshall and Danny Trevathan were on hand at practice, but wore a baseball cap and a visor, respectively, taking mental repetitions.

Marshall's recovery from the foot injury he suffered at San Diego last Dec. 14 has been rigorous. He said he has yet to begin running, but expects that to happen "fairly soon." He added that he remains on track to return by the start of training camp, which can be no sooner than July 31.

"I think I'll be right on time," said Marshall, who had two screws inserted in his foot during his surgery. He expects they will remain in his foot during the season and be removed after the year.

With Marshall and Trevathan out, Todd Davis, Steven Johnson, Corey Nelson and Lamin Barrow all saw extra work.

"I thought they looked good. And I sit here and try to help those guys out as much as I can," Marshall said. "I try to give them some technique points and different things like that, because I want to see everybody do good, honestly.

"Obviously, it's about winning a job, but to me, it's not about withholding information. I'd rather have a guy know as much as I know, and then we go battle it out mano a mano."

8. EDGE RUSHERS MAKE AN IMPACT.

DeMarcus Ware and Von Miller consistently got into the backfield during Wednesday's work, which is what you expect with from the Pro Bowl pair. Both were able to blow up plays working from outside linebacker, and Miller recovered a fumble and picked it up for what would have been a touchdown.

Backup outside linebackers Lerentee McCray, Shaquil Barrett and Chase Vaughn were all effective at getting into the backfield and disrupting Osweiler and Zac Dysert. They had their chance for more repetitions with first-round pick Shane Ray still a few days away from returning, and delivered.

Kubiak expects Ray to do some individual work next week.

"He's in a lot of treatment. He wants out of that and wants on the field, but we're going to go about this slowly and go about it the right week."

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9. WHO ELSE HOPPED INTO MY NOTEBOOK?**

Defensive end Derek Wolfe also had a strong day up front. In game conditions, he would have notched a sack on a stunt up the middle, but given the non-contact nature of the work, he held up and let Manning fire a pass downfield. He also blew up another play with a quick move inside Vasquez, which got him into the backfield.

Running back Juwan Thompson did well at reading the development of his blocks and hitting the hole authoritatively. One of his most impressive runs came when Paradis and rookie Andre Davis created a massive hole through which Thompson galloped.

Tight end/fullback James Casey runs crisp routes and has a knack for getting open underneath. He can be a versatile receiving target moving around and allows Broncos to change their formation without changing personnel, which will help the offense maintain a quick tempo. Casey caught 34 passes for 330 yards and three touchdowns in his last season under Kubiak and Dennison with the Texans (2012), so he has more pass-catching ability than some realize.

Kubiak noted May 2 that Ty Sambrailo would begin OTAs behind Chris Clark at right tackle, which will allow him to get his footing. But Sambrailo looked the part, driving off the snap and showing good quickness to spring Thompson and Ronnie Hillman for some solid gains.

Rookie cornerback Lorenzo Doss was known for his pick-off prowess, and he ended practice with an interception of Zac Dysert. But running back Kapri Bibbs also deserved notice on the play with an outstanding block to give Dysert an extra second to throw.

Dysert and Osweiler each had their moments. Dysert looked smooth moving out of play-action, and Osweiler became more consistent as the day progressed, overcoming some early misses. Osweiler's timing with his new teammates at tight end and wide receiver improved throughout the day.