7 most improved units in the NFL

With free agency and the draft in the rearview mirror, teams around the league have done all they can to improve their rosters ahead of the 2016 season.

Virtually every team had glaring weaknesses entering the offseason, but some did a better job than others of addressing those holes.

Here are the seven units around the NFL that made the most dramatic upgrades:

Bears' inside linebackers

2015 starters: Shea McClellin, Christian Jones
2016 projected starters: Danny Trevathan, Jerrell Freeman

The Bears managed to turn one of the worst units in the NFC into one of the best during free agency, adding two of the league's premier inside linebackers. While Trevathan and Freeman aren't particularly flashy signings, they're ideal fits in Vic Fangio's defense, which relies on stellar play from the middle of the unit. As a pairing, Trevathan and Freeman aren't the stoutest in run defense, but they're outstanding in coverage. The group that continuously caused Chicago's defense to fail in 2015 should be its defining strength in 2016.

Cowboys' running backs

2015 starters: Darren McFadden, Joseph Randle
2016 projected starters: Ezekiel Elliott, Alfred Morris

One forgotten part of the Cowboys' disappointing 2015 season was McFadden's effectiveness as lead back. He broke 1,000 yards rushing and, at times, looked to have regained his signature explosion. The fact Elliott still represents a massive upgrade to the running game is a testament to the rookie's talents. He's a prototypical three-down back, and with the help of a dominant offensive line, should propel the Cowboys' offense to among the best in the league. The addition of Morris, who's capable of being the featured back himself, means Dallas suddenly has one of the best one-two punches in the league.

Jaguars' secondary

2015 starters: Davon House (CB), Aaron Colvin (CB), Jonathan Cyprien (S), Josh Evans (S)
2016 projected starters: Prince Amukamara (CB), Jalen Ramsey (CB), Tashaun Gipson (S), Jonathan Cyprien (S)

Head coach Gus Bradley's defensive scheme has always revolved around having a dominant secondary, and after several seasons of working with subpar players, he finally has the pieces to run the defense he wants. Amukamara and Ramsey are comfortable in both zone and man coverage, and should bring some much-needed playmaking ability. Gipson isn't a top-notch safety, but his presence at free safety should allow Cyprien to move to strong safety, which better suits his skill set.

Texans' backfield

2015 starters: Brian Hoyer (QB), Alfred Blue (RB)
2016 projected starters: Brock Osweiler (QB), Lamar Miller (RB)

Whatever you think of Osweiler's ability to be a true franchise quarterback, or if he's worth the huge deal the Texans handed him in free agency, there's little doubt he's an improvement over Hoyer. The Texans' season was doomed by Hoyer's four interceptions in the playoffs, and Osweiler has shown he's capable of managing the game and avoiding turnovers. Houston's offense should run through free-agent addition Miller. He has the talent to carry the offensive workload, and provides the consistency and big-play ability that Blue lacked.

Raiders' secondary

2015 starters: David Amerson (CB), DJ Hayden (CB), T.J. Carrie (CB), Nate Allen (S), Charles Woodson (S)
2016 projected starters: Sean Smith (CB), David Amerson (CB), T.J. Carrie (CB), Reggie Nelson (S), Karl Joseph (S)

The Raiders used free agency and the draft to attack their weaknesses on the defensive side of the ball, upgrading their defensive line and linebacking corps. However, no unit saw a bigger boost than the secondary. Losing Woodson hurts, but Nelson has the range to play a similar role, and his pairing with rookie Joseph should be productive. The addition of a true shutdown corner in Smith means Oakland now boasts one of the most intimidating secondaries in the AFC.

Giants' defensive line

2015 starters: Robert Ayers (DE), Johnathan Hankins (DT), Cullen Jenkins (DT), Jason Pierre-Paul (DE)
2016 projected starters: Olivier Vernon (DE), Damon Harrison (DT), Johnathan Hankins (DT), Jason Pierre-Paul (DE)

The Giants have always relied on a dominant defensive line and pass rush to win games, but in recent times, the unit has failed to deliver. The big-money signing of Vernon gives the Giants an edge-rusher who, while inconsistent, has the upside of an elite defender. Pierre-Paul wasn't nearly as effective in 2015 as he was before his injury, but he should be improved thanks to a full offseason. If he's able to produce at close to his previous level, he could provide the biggest spark to the unit. Harrison might be the offseason's most under-the-radar signing, and should immediately bolster the team's run defense, forming a scary inside duo with Hankins.

Titans' running backs

2015 starters: Antonio Andrews, Dexter McCluster
2016 projected starters: DeMarco Murray, Derrick Henry

The Titans' lack of talent in their backfield hindered their offense in 2015. To avoid a repeat in 2016, they traded for Murray and drafted Henry. The duo should ease the burden on Marcus Mariota and open up the rest of the offense. Murray struggled to such a degree last season that many wondered whether he's truly good enough to be a featured back, and Henry faces similar questions about his skill set. However, given that the Titans arguably had the league's worst running back group last season, they're still two massive upgrades.