ENGLEWOOD, Colo. —The Broncos entered the 2014 season with the bulk of the pressure on the defense making marked improvements. After bringing in a group of outstanding free agents, the defense made the leap to the top with a dominant rushing defense and the passing defense known to fans as the "No Fly Zone."

With five Pro Bowlers on this side of the ball, comebacks from injuries, newcomers stepping up and a franchise record-setting defense, there was no shortage of impressive moments this year.

We can begin with the newcomers, who made an impact from the first game. Though the star additions made waves in deciding to sign with Denver, some new to the bright lights made big moves in the season opener against Indianapolis.

Brandon Marshall started at weakside linebacker with Danny Trevathan out, and though Marshall had to make a tough transition to fill Trevathan's big shoes, you could see his potential against Indianapolis. In the third quarter, the Colts were down 24-7 and desperately looked to make up ground quickly. Their first drive of the second half began with great field position and they marched close to the goal line. After a short run and two short passes stopped for hardly any gain, the Colts decided to go for it on fourth down with only a yard separating them from the end zone. The quarterback sneak to Andrew Luck was stuffed up the middle and Luck tried to bounce left around the pile and give a second effort. But Marshall was there to stand him up and stop forward momentum, giving the Broncos the ball.

As Marshall progressed through the season, he fulfilled the potential he showed in the first game, becoming a terrific run-stopping linebacker who filled the gaps and made tackles whenever he needed to. As part of a Broncos' rushing defense that set the team record for rushing yards per game allowed, Marshall stepped into a difficult role and showed poise, leadership and great skill in a key role.

The other player to show up in the first game—in his first-ever NFL game, no less—was rookie cornerback Bradley Roby. The Colts needed a touchdown drive to tie the game with three minutes to go, and they started moving the chains. They crossed midfield with a 12-yard pass, and then Luck tried to take advantage of Reggie Wayne on rookie cornerback Bradley Roby. After two incomplete passes, a false start and third-down completion leaving them with six yards to go for a first down, Luck tried to find Wayne over the middle with Roby draped on him. Roby played it perfectly and deflected the ball to the turf, ending the Colts' comeback hopes.

The first game of the season had shown just a taste of what the Broncos' defense could do, and they were focused on improving even more. One of the components of what would be the league's No. 2 overall defense was a dominant run defense, which was evident from Week 1.

Week in and week out, the run defense could be depended on like clockwork in holding opponents well below 100 yards per game. Terrance Knighton forced opposing offensive lines into disarray, and in the second game, he even came up big in pass defense. Kansas City had to try their luck at a fourth-down conversion just short of the goal line. Unlike Andrew Luck in Week 1 at the goal line, Alex Smith tried to go through the air. But Knighton grazed the pass at the line, knocking it off its path enough to fall incomplete. Though the lineman's presence was more often felt in the run game, he could also put some pressure on against the pass.

Running against the Broncos wasn't the only difficult part for opponents – so was passing. With Aqib Talib and Chris Harris Jr. on the wings and Rahim Moore and T.J. Ward eyeing the field from downfield, quarterbacks had little room for error against them. Talib and Ward were offseason free agent signings, and played at the level familiar to those who had watched them before in their previous Pro Bowl years. Ward had two picks and two sacks to go along with a versatile skill set that let him play nickel linebacker about as naturally as safety. Talib had one of the best seasons of his career with four interceptions (two returned for touchdowns), one forced fumble, 18 passes defensed and one sack, and he was named AFC Defensive Player of the Week after their road game against the Chargers.

Moore was no slouch either with a career-best four interceptions (including two in the Week 1 opener), a forced fumble and a fumble recovery. Like a few other Broncos battling back from a scary injury, this was a redeeming season for Moore, who had nearly lost his leg to the rare acute compartment syndrome.

For Chris Harris Jr., too, this year was a particularly special one. He's had a difficult road ever since trying to make the roster as an undrafted player, but his goal of making the Pro Bowl got a bit more difficult after he tore his ACL in January of 2014. But he rebounded as quickly as any professional athlete has to this point, returning to the field in about six months for practice, ready for the beginning of the season shortly after that. That he was even back in time for the regular season was an incredible feat, but his play on the field was a dominant level that we hadn't seen before from him. He didn't allow a single touchdown all year and got that first Pro Bowl nod.

In one of Harris' best games of the season, the Week 8 Thursday-night matchup against San Diego, he had a night to remember. He had a great game with four tackles and an interception, but the day was all the more special because of what happened after it concluded. With the Broncos set to take off on a three-game road trip, Harris and his wife, Leah, decided to induce labor that evening so he could be with Leah for the birth of their new daughter Aria and spend some time with her.

Harris' comeback was a path that Von Miller also traveled over the previous offseason. But he, too, came back from a difficult knee injury and performed back at the level fans are used to seeing, earning a Pro Bowl selection and a second-team All-NFL pick.

DeMarcus Ware joined Miller as the Broncos' other dangerous pass rusher, after he was signed in free agency, along with Talib and Ward. Ware completed the triumvirate of elite free agency signings, as all three of them returned to the Pro Bowl this season. The veteran defensive end was a dynamic addition, and especially helped spur Miller to greater success as the two raced to see who could get the most sacks.

Ware came out victorious in Week 7 against San Francisco, but that game was a success for the entire pass rush. Those two sack artists combined for five sacks (Ware with three, Miller with two), and Malik Jackson had one. San Francisco's offense was out of sync the entire night, failing to run efficiently or protect well. Ultimately the 49ers scored just two touchdowns to the Broncos' seven, making for one of Denver's most dominant games on both sides of the ball.

As the season wore on, the Broncos stayed at the top or near the top in the main defensive categories. They finished as the best team in the league in passing yards per play allowed, No. 4 in rushing yards per play allowed and No. 2 in overall yards per play allowed. With that basis, they certainly had one of the better defensive seasons of any team this year.