Tampa Bay Buccaneers rookie defensive lineman DaVonte Lambert was inactive for the team's first game of the regular season, but that was hardly a demoralizing start to Lambert's professional career. The simple fact that he was on the roster after arriving as an undrafted free agent out of Auburn represented a great step forward in chasing his NFL dream.

Then there's this: Just 14 days later Lambert was on the field for 51 of the Buccaneers' 65 defensive snaps in a wild, last-minute loss to the Los Angeles Rams. There was barely any time for Lambert to get adjusted to the fact that he was truly in the league before he was suddenly pressed into a serious role.

WATCH: WEDNESDAY'S PRESS CONFERENCES

Things developed rapidly for Lambert for an unfortunate reason, or series of events, for his team.  Veteran defensive end George Johnson was lost to a season-ending injury in the preseason. Defensive end Jacquies Smith, one of the team's best pass-rushers, tore an ACL in that Week One win in Atlanta and was lost for the season. That led to Lambert being active in Week Two at Arizona and getting on the field for 29 snaps.

Lambert's playing time in the Cardinals game probably would have been far less if not for the first-half ankle injury suffered by starting right end Robert Ayers. Ayers was not able to play in Week Three and the Bucs wanted to keep ends Noah Spence and Howard Jones in designated pass-rusher roles, so Lambert got the start at right end and fellow undrafted rookie Channing Ward also saw his first bit of NFL playing time.

"He did fine, again, for getting as much play time [as he did]," said Head Coach Dirk Koetter of Lambert's starting debut. "I think he was in the low 50s as far as his snaps, and I think Channing Ward was in the low teams as far as his snaps. Our depth on the D-Line is definitely being tested earlier, with the guys that we've lost, unfortunately. Those two guys are getting to play a lot. I'm encouraged by their effort and they are getting better."

It's been a heady rise, but Lambert is trying to stay grounded so that he can make the most of this opportunity.

"I've had a lot of guys come up to me and congratulate me on those things, but I have to keep pushing and keep fighting," he said. "The league is very different than college. Bigger guys and they're technicians, so you have to work on your skills every day."

READ: 3 KEYS TO DEFEATING THE BRONCOS

Lambert is 6-2 and 282 pounds and was actually listed as a defensive tackle during training camp. The Buccaneers kept him and fellow undrafted rookie lineman Channing Ward through the cuts to 53 in part because they believed both players were versatile enough to play inside and outside. Lambert was the choice to start against the Rams because he was considered more stout at the point of attack and the Rams were expected to emphasize the run. The Buccaneers' defense actually played the run quite well against Todd Gurley and the Rams for most of the game until Gurley got in some longer scampers late in the second half.

Lambert is trying to help the Bucs' defensive front seven remain stout while Ayers is out by paying attention to the details he's getting from both the coaching staff and Ayers himself.

"Even though Rob's not playing, he's still in the film room, he's telling us everything – 'This is what you need to watch for,'" said Lambert. "It's good to have a guy like that around, especially for me, a young guy, to have him teach me those things.

"It's more about footwork and heads, and seeing things like pre-snap indications and stuff like that. The biggest thing is you have to keep your eyes on the key. The key will take you to the ball every time."

• The defending-champion Broncos opened the season on Sept. 8 as three-point underdogs at home to the team they had beaten in Super Bowl 50 the previous February. The obvious reason for this was the Broncos' unknown quantity at the game's most important position – 2015 seventh-round pick Trevor Siemian had won the starting quarterback job after the retirement of Peyton Manning and the free agency departure of Brock Osweiler.

Even after Siemian was announced as the opening-day starter, he was largely seen as a temporary placeholder until first-round draft pick Paxton Lynch was ready. Fortunately for the Broncos, it looks like they'll have plenty of time to groom Lynch, as Siemian has performed well during Denver's 3-0 start.

READ: BUCS-BRONCOS SERIES HISTORY

One person who could have seen this coming: Buccaneers practice-squad tight end Danny Vitale. A sixth-round pick by Tampa Bay this past spring, Vitale was a teammate of Siemian's at Northwestern for three years.

"It's definitely not a surprise to me, especially having known him for four years or so," said Vitale. "I would say the one thing about him, which I think a lot of people have found out, is just the composure that he has. He's always calm, cool, collected. What I liked about him personally was he was a little bit of a goofball, too, all the time, just a fun guy to be around. I'm not surprised he's seeing a lot of success."

Vitale got a snapshot of Siemian's natural poise the very first time the future Buccaneer took the field for Northwestern. In a wild back-and-forth game at Syracuse, Siemian subbed in late for starting quarterback Kain Colter and directed a 75-yard, game-winning touchdown drive in a 42-41 decision. Vitale caught one pass in that game; the winning score went to Demetrius Fields on a nine-yard pass with 44 seconds to play.

"He was like 'QB 1B,'" said Vitale of the Wildcats' quarterback arrangement at the time. "We had another quarterback in Kain Colter, and every time we needed a big drive to finish out the game or a two-minute drill, Trevor was always the guy who would come in. "Just the composure and everything that he's got is unbelievable, and unparalleled in my opinion."

Still, it's safe to say that Siemian's NFL career began quietly when he was the last of seven quarterbacks drafted in the spring of 2015, going 250th overall out of 256 picks. The Buccaneers' Jameis Winston and Tennessee's Marcus Mariota went 1-2 in that draft and have started since Day One, but the only other drafted QB from that spring that is currently starting is Siemian in Denver.

READ: BUCS' PASS-CATCHERS STEPPING UP FOR WINSTON

Vitale thinks the key was getting selected by the Broncos and decision-makers John Elway, the general manager, and Gary Kubiak, the head coach.

"I've always kind of seen it and kind of known," said Vitale of Siemian's promise. "Especially [in] a pro-style offense, I think that's a great fit for him. And then when you've got coaches and staff with Elway and Kubiak who can develop a guy that's just a raw talent, I think he just ended up in a great situation. I'm not surprised at all, to be honest with you."

• The Buccaneers filled out their practice squad in time for the week's first workout, signing wide receiver Jonathan Krause on Wednesday morning. There was an available spot on that 10-man unit after last Friday's promotion of tight end Alan Cross to the active roster.

Krause went to training camp with the Buccaneers after being claimed off waivers from the Philadelphia Eagles in late July. He played in all four preseason games and recorded four catches for 73 yards, with a long of 41. He also got a look as a punt returner, gaining 41 yards on three runbacks.

The 5-11, 190-pound Krause was waived during the league-wide roster cuts to the 53-man regular-season limit. He played his college ball at Vanderbilt and came into the league with the Cleveland Browns in 2014 as an undrafted free agent. He played in two games for the Eagles last season, catching two passes for 11 yards.

The Buccaneers had six receivers on the active roster after last week's promotion of Freddie Martino (including the injured Cecil Shorts), but only one on the practice squad in Jeremy Butler.

• The Buccaneers' first injury report of Week Four is succinct and largely unchanged from last week.

The report lists five players, including the four who were out due to injury in the game against Los Angeles: defensive end Robert Ayers, running back Doug Martin, WR Cecil Shorts and TE Luke Stocker. The new addition was center Joe Hawley, who suffered an ankle injury on Sunday and briefly left the game, though he did return.

None of those five participated in practice on Wednesday.

The Broncos have a much longer injury report but one that will probably have less of an impact on the game this coming weekend. Four players did not practice on Wednesday, including defensive end DeMarcus Ware, who missed Denver's Week Three game in Cincinnati due to a forearm fractured suffered the previous week against Indianapolis.

The other three held out on Wednesday were safety Shiloh Keo (knee), linebacker Corey Nelson (ankle) and tackle Donald Stephenson (calf); only Stephenson, the Broncos' right tackle, is listed as a starter. Starting safety T.J. Ward was limited in practice by a neck ailment.