ENGLEWOOD, Colo. –Historically, middle linebackers represented the anchor of the defense.
Known as hard hitters who were key cogs against smashmouth run games, middle linebackers called out the plays and were the vocal leaders on defensive units.
In today's NFL where passing yards per game are up nearly 10 percent over the past decade, defenses have had to adjust as offenses spread the field out and throw the ball more often.
That means more nickel and dime packages on the field to counter the three, four and five receiver sets that have become popular among offenses.
"Our third corner last year, our sub packages of at least three corners, we took up I believe 65, 66 percent of our snaps last year," Defensive Coordinator Jack Del Rio said. "So you're talking about a guy that's playing the majority of the snaps as opposed to a third linebacker."
The player most likely to come off the field in place of the extra cornerback was the team's middle linebacker.
In Denver's defense last year, the team's middle linebackers combined to play about 70 percent of total snaps – roughly the same number as the team's third cornerbacks.
"I think if you look at where the league is and where we are, 65 percent of our snaps last year were nickel," Executive Vice President of Football Operations John Elway said. "I'm not trying to downplay the importance of (the middle linebacker position), but nickel is so important, too."
With strongside linebacker Von Miller playing at an All-Pro level and as an every-down threat as both a pass-rusher and a run-stuffer, he wasn't coming off the field. On the weakside, Wesley Woodyard also showed his versatility against both the run and pass as he was the only player in the league – and just the 12th player in the last 30 years – to record at least 100 tackles, five sacks and three interceptions in the same season.
"If you don't have a guy who is a bona fide monster in the middle that's never going to come off the field, he can be the first guy off," Del Rio said. "If you're going to leave two backers out there, he can be the first guy off. It's just you're going to play your two strongest guys all the time, if they can handle it. Then the third guy, whoever that is, needs to play when it's base. Then when it goes sub, he can come off."
The strategy there varies scheme-by-scheme and team-by-team around the league, based on club's strengths defensively.
The Broncos were fortunate to have the talents of cornerback Chris Harris Jr. and Tony Carter, who rotated as the team's nickel cornerbacks in 2012. The two players combined for five interceptions and four defensive touchdowns last year.
For a team like San Francisco that has perennial Pro-Bowler Patrick Willis at middle linebacker, the coaches find ways to keep him on the field.
"If you have a special 'Mike' that's a special player, he's going to play every down," Del Rio said. "Patrick Willis doesn't come off the field for San Francisco. So there are guys out there that are superior players."
"That just varies by team, by personnel."
Joe Mays and Keith Brooking were the two players to start at middle linebacker for the Broncos last year. While the two did combine to start every single game, they played the lowest percentage of snaps of any of the team's 11 typical defensive starters.
Brooking, who played in all of the team's 16 regular-season games with 14 starts, participated in 42.3 percent of the defensive snaps in 2012. That number was fewer than Tony Carter, who rotated between nickel and dime cornerback and saw time on defense in only 13 of the Broncos games.
"The third corner is playing more like a starter now," Del Rio said. "You still trot out your starters before the game, and the nickel typically doesn't run out (of the tunnel), but if they start in 11-personnel, he will. So that position has become more and more important."