Ranking the most improved NFL teams

Unrestricted free agency comes to a halt this week, as UFAs turn into street free agents, meaning they no longer count against a team's ability to get a compensatory pick in 2017.

While there will be signings and possible trades from now until training camp and beyond, a clear picture has emerged in determining which teams improved the most during the offseason. Fifteen of the 20 teams that didn't make the playoffs last year had bad defenses, surrendering 24.2 points per game or more.

Most of the efforts of the non-playoff teams went into signing or drafting defenders. Most playoff teams, however, didn't invest big money into defensive acquisitions. The exceptions were the Washington Redskins, who signed cornerback Josh Norman for $15 million per year, and the Arizona Cardinals, who traded for pass-rusher Chandler Jones, who has one year left on his deal at $7.8 million. All the other deals for defenders on teams that made the playoffs came at bargain prices.

Bottom line, the teams that improved on defense have the best chance of winning the offseason. Here are the six teams that improved the most, in order:

1. Jacksonville Jaguars

The draft capped off a great offseason. Jaguars general manager Dave Caldwell added two potential rookie stars in cornerback Jalen Ramsey and linebacker Myles Jack. The defensive line improved with the signing of Malik Jackson. The secondary got better with the addition of free safety Tashaun Gipson, who has the range to allow coach Gus Bradley to let his corners play better in man and in Cover 3. Throw in the debut of last year's first-round pick, defensive end Dante Fowler Jr., and the Jaguars will have five defenders with Pro Bowl potential or accomplishments.

Caldwell said last year that you can't necessarily rely on rookies to make a big improvement. That's why the signing of Prince Amukamara to a one-year contract helps. He takes pressure off Ramsey and buys time for the rookie to develop. The Jags gave up 28 points per game last year. If all works out, they should shave four points per game off that total.

A bonus for Jacksonville was adding halfback Chris Ivory. They now have a running attack that should help the defense.

2. New York Giants

When your owner lets you spend more than $200 million on defense in free agency, you better be improved. The pressure is on general manager Jerry Reese, who made the call on the signings, and defensive coordinator Steve Spagnuolo, who now has to show improvement on the field. The Giants gave up 27.6 points per game last season and had very little pass rush.

New signing Olivier Vernon and Jason Pierre-Paul, who's back for a full season, will provide the pass rush. Janoris Jenkins, Dominique Rodgers-Cromartie and first-round pick Eli Apple offer about as talented a three-cornerback coverage group as you can find in the league. Damon Harrison will be the run-stuffer. Keenan Robinson and Kelvin Sheppard add more depth at linebacker.

Figuring new coach Ben McAdoo should get 25 to 26 points per game out of the Eli Manning-led offense, all the Giants need to do is cut three or four points per game off the defense to have a winning record.

3. Tennessee Titans

When you go 3-13, you have nowhere to go but up. GM Jon Robinson has fans looking to the skies and seeing good things. This was the one team that may not have focused on defense, but it sure added talent. Robinson wanted to emphasize defense, but great offensive talent kept falling into his hands.

The Philadelphia Eagles gave him DeMarco Murray, and then halfback Derrick Henry fell to him in the second round. Center Ben Jones and first-round right tackle Jack Conklin fill out a talented offensive line that plans to play smash-mouth football.The Titans took six defensive players in the draft and added four more in free agency.

Maybe they need next year's draft -- when they'll have two first-round picks -- to make a big jump on defense, but they have done enough to think about a three- or four-game jump in the standings.

4. Oakland Raiders

GM Reggie McKenzie fixed the offense during the 2014 and 2015 offseasons. McKenzie wants an old-school Raiders line like it had in the 1970s, and the signing of guard Kelechi Osemele gives them one of the best offensive lines in football. With quarterback Derek Carr and weapons across the board, Oakland has the offense to put up points. The mission this offseason was to fix a defense that gave up 24.9 points per game.

The secondary now has cornerback Sean Smith and safeties Reggie Nelson and Karl Joseph. Bruce Irvin adds speed off the edge, and the re-signing of Aldon Smith should add a pass rush down the stretch. At 7-9, the Raiders were a team on the rise last season. This year's moves could put them in playoff contention.

5. Tampa Bay Buccaneers

GM Jason Licht worked well with former coach Lovie Smith the past two years and fixed the offense, adding quarterback Jameis Winston, wide receiver Mike Evans, tight end Austin Seferian-Jenkins and offensive linemen Donovan Smith and Ali Marpet.

This offseason, Licht took the Noah's Ark approach and helped a defense that surrendered 26.1 points per game. He added two pass-rushers in Robert Ayers and Noah Spence. He added two cornerbacks in Brent Grimes and Vernon Hargreaves III. Linebacker Daryl Smith will help the young linebacking corps.

The Bucs had three studs on defense last season -- defensive tackle Gerald McCoy and linebackers Lavonte David and Kwon Alexander. One more solid draft should put this defense over the top.

6. Chicago Bears

Here's the sleeper of the improved teams. First-round pick Leonard Floyd and inside linebackers Danny Trevathan and Jerrell Freeman finished the rebuilding of the linebacking corps. The team is strong along the offensive line with the signing of Bobby Massie at right tackle and the drafting of guard Cody Whitehair in the second round. Defensive end Jonathan Bullard and veteran Akiem Hicks makes the defensive line bigger and stronger.

Coaches John Fox and Vic Fangio cut 2.8 points per game off a defense that allowed 27.6 before they arrived. Now, the Bears are assembling talent to shave more points off their average.