When narrowing down the NFL's best linebacking groups, they all have two things in common: versatility and depth.
The top-tier units not only focus on sacks and rushing the passer, but can play the run, set the edge and cover -- ultimately, they're the most well-rounded. Alongside versatility, they have one (if not multiple) players who never leave the field because their athleticism and skill sets allow them to take over football games. And if those impactful players head to the sideline, there isn't a significant drop-off in production when the next guy comes in.
There are several elite linebacking corps -- that each have these important qualities -- heading into the 2017 NFL season. Here's a look at my top five:
1) Denver Broncos
The Denver Broncos still possess one of the league's best pass rushers and linebackers in Von Miller. He followed up his Super Bowl-winning season with 13.5 sacks in 2016 and remains an incredible force. Yet, this group doesn't just have one great player. It has depth. The production doesn't fall off when one of the starters is out -- they are all fast, strong and physical. Last season, then-defensive coordinator Wade Phillips was able to do a lot of different things scheme-wise because of their versatility, and I expect new head coach Vance Joseph and defensive coordinator Joe Woods will be able to do the same. Along with a stellar pass rush that helped Denver rank third in sacks last season, the Broncos linebackers are stout and physical in the run game and great in coverage.
2) Kansas City Chiefs
The Chiefs might not be as athletic as some of the other teams on this list, but they play the run and get after the quarterback collectively better than any other group in the league when healthy. Yes, the Chiefs have some studs in the secondary, but this defense is successful because of its linebackers. They cover well, and as far as the run game and rushing the passer go, they're as good as anybody. The Chiefs control the line of scrimmage and have strong, physical players in this unit. There isn't just one player who stands out in this group. They are all solid.
3) Carolina Panthers
Some say Luke Kuechly is the best linebacker in the league, and his play certainly gives people reason to think so. We could tell when he wasn't on the field last season. Kuechly and veteran Thomas Davis are able to control the entire Panthers defense from the linebacker position. Their impact on the field -- how they diagnose and sniff out plays before they begin -- demonstrates their knowledge of the game. Throw in young hybrid Shaq Thompson, who fits right in with what Carolina does in coverage, and this is a dangerous position group. Thompson can cover tight ends and running backs or he can be sent on certain blitzes. The Panthers could have the best starting unit in the league, but the two teams above have a little more depth.
4) San Francisco 49ers
New general manager John Lynch is building a stout defense in a short time, as reflected in the spirit of Lynch's Tweet on Monday about adding veteran pass rusher Elvis Dumervil: "Just added another stud to harass QBs." Dumervil joins a consistent Ahmad Brooks, former All-Pro NaVorro Bowman (who's returning from injury), experienced former Super Bowl MVP Malcolm Smith and Reuben Foster, one of the best rookies at the position. When Bowman and Patrick Willis played alongside one another, they were electric. If Foster -- who can be not just the best defensive rookie this season but the best first-year pro, period -- digests the defense, he could assume the Willis role in 2017.
5) Oakland Raiders
There are so many teams that could've made a case for the fifth spot. But I can't leave the Raiders off this list because the versatile Khalil Mack is one of the most disruptive players in the NFL. He was an All-Pro at two positions in the 2015 season, and he's still learning how to shift between linebacker and defensive end. Although Mack is listed as a defensive end in a 4-3 defense, he has the ability to play either position and is still capable of doing linebacker duties for the Raiders. Mack will fight for the Defensive Player of the Year award with J.J. Watt and a few other players for a long time.