TAMPA, Fla. -- After two losses, first-year Tampa Bay Buccaneers coach Dirk Koetter wants to change the culture of a team that hasn't won a playoff game in 13 years. He'll have a good model of what he's seeking on the other sideline when the defending Super Bowl champions come to Raymond James Stadium.

"When I'm talking about the culture ... I'm talking about the 53 players, the 10 practice-squad guys and however many coaches we have," Koetter said. "The best teams that I've been on beat with one heart, and they count on the guy next to them to do their job every time, and they win and lose together."

The Buccaneers (1-2) have dropped two straight games, a lopsided 40-7 loss at Arizona and a 37-32 setback on Sunday against the Los Angeles Rams that included a 70-minute lightning delay with two minutes left in the game. Tampa Bay moved into scoring position at the Rams' 15-yard line and had five shots at a game-winning touchdown in the final minute but came up short.

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Denver is off to a 3-0 start despite starting an unknown commodity in second-year pro Trevor Siemian at quarterback. The former Northwestern player had a coming-out party in Sunday's win over the Cincinnati Bengals with four touchdown passes.

"He's obviously very young, and this will be his fourth time as a pro," Broncos coach Gary Kubiak said Wednesday. "He's handled himself really well. ... I think the good thing is he knows he's on a good football team and tries to stay within himself and do his job. We've got a long way to go, but he continues to work at his trade each and every day."

In throwing four touchdown passes Sunday, Siemien was just the ninth player in the last 40 years to do so in one of his first five NFL games. The last one? Tennessee's Marcus Mariota against the Buccaneers in last year's season opener.

The Buccaneers brought in defensive coordinator Mike Smith, but the results have actually gotten worse. Tampa Bay is giving up 33.7 points per game, the most in the NFL and the most ever for a Buccaneers team after three games in the 41-year history of the franchise.

"You have to realize that of whatever the number is, 101 points or whatever it is, our offense has contributed way, way too much for that," Koetter said. "We moved up one spot in turnover margin, from 32nd to 31st."

Buccaneers quarterback Jameis Winston typifies the highs and lows of a young Tampa Bay team -- he leads the NFL with eight touchdown passes but is also one interception off the league high as well with six, to go with two costly fumbles he has lost as well.

In Sunday's loss to the Rams, Winston reset his career high with 405 passing yards but saw a fumble returned 77 yards for a touchdown and his only interception of the game set up another Los Angeles touchdown. There is small progress -- the Tampa Bay defense, held without a takeaway in the first two games, came up with two Sunday, including Kwon Alexander's interception return for a touchdown.

The Bucs have a daunting two weeks ahead, facing both teams from last year's Super Bowl, first the Broncos and then a Monday night game at Carolina, which has owned them in recent years. Tampa Bay will need a major upset to avoid going into its Week 6 bye with a disappointing 1-4 record.

The Broncos are in a very different place from the Buccaneers, trying to sustain a high level of success despite a lack of proven experience at quarterback. There are higher expectations when a franchise has won multiple Super Bowls, and Kubiak understands the challenge of repeating a team's success over time.

"This is a tough league," he said. "You've got 32 organization. Everybody puts in the work and grinds at this thing. It's a very, very difficult league. I think what you're always looking for is consistency -- consistency in your preparation, consistency in your approach from the top down. I think that's what you're looking for as an organization."