A championship window for an NFL team can be a curious thing. It is usually never long, it is almost never revolving and it can close much quicker than anyone would expect. It can also open unexpectedly, as the Cowboys discovered in 2016, when they went from the ultimate “win-now” team paying off a high-interest loan on Tony Romo’s contract to a team looking set for the long haul thanks to the emergence of Dak Prescott and Ezekiel Elliott as rookies.

The window does usually revolve around a quarterback, the only player who can drastically alter a team’s short- and long-term prospects. Jerry Jones was willing to play the role of Mr. Shovelstuff, pushing all his chips into the center of the table in pursuit of a ring while Romo was still capable of playing high-quality football. The Cowboys built an impressive wall of talent on the offensive line, but they also stumbled into the extension of their championship window with Prescott in the fourth round.

Sometimes it’s better to be lucky than good. It’s also usually better to be patient than aggressive in roster building, but knowing when the time is right to take a calculated strike is critical too.

Entering the 2017 season, there is a group of teams who are backed into a corner of sorts, seeing a championship window close and being forced to go for the gusto. These teams will likely be aggressive in free agency and also keep an eye toward immediate impact when it comes to the draft.

Not all of these teams are identical, and there’s nothing wrong with being on this list. Being forced to win now is certainly better than not being able to win at all.

Easily the easiest team to identify on this list. GM Steve Keim confirmed this offseason the teams plans to be aggressive, given the state of the roster. Arizona as a whole is loaded with talent, a lot of it young. But there are some critical pieces heading down the homestretch that make this a pretty huge year for the Cardinals.

Following a disappointing 2016 season, Carson Palmer thought about hanging up his cleats. How serious he was about it, we’ll never know, but certainly he’s a more likely retirement candidate than, say, Ben Roethlisberger. Palmer was better than people give him credit for last year, though, and was actually quite strong down the stretch. In his last five games, Palmer completed more than 61 percent of his passes, averaged 260 yards a game and 7.11 yards per attempt, and threw 11 touchdowns to three interceptions. That included a game in a monsoon against the Dolphins. If Palmer gets back to 2015 form, or even just plays most of the season the way he played at the end of 2016, the Cardinals will compete in the NFC West.

Does Carson Palmer have enough left in the tank for one last run? USATSI

Larry Fitzgerald has indicated he wants to go as Palmer goes, and was a viable candidate to retire before 2017 too. During a “slow” year in 2016, he led the NFL in receptions, topped 1,000 yards and caught six touchdowns. The Cardinals need to put some weapons around Fitz after Michael Floyd departed, but with a healthy John Brown, a stud receiving back in David Johnson and other burners on the roster (J.J. Nelson, Jaron Brown, etc.), they have plenty of ammo to score points.

Defensively, we can’t be sure if Calais Campbell (somehow just 30) will be back or if Chandler Jones will be under contract (Jones is a prime candidate to get the franchise tag; Michael Bidwill says the team will use it on him if necessary). There are a number of other starters (Frostee Rucker, Sio Moore, Marcus Cooper) who are free agents as well.

For as close to the Super Bowl as the Chiefs were in the 2016 season -- No. 2 seed in the AFC, a close loss to the Steelers in the divisional round -- they also felt very far away from winning a title. That’s just how you feel when you prevent an opponent from scoring a touchdown in a home playoff game and walk away with a loss.

The Jamaal Charles era in Kansas City is likely ending, with one of the two best running backs in Chiefs history -- Priest Holmes would be the other guy in the dicussion -- an expected cap casualty this offseason. Spencer Ware is a more than capable feature back in Andy Reid’s system, though, and the Chiefs will bring back Travis Kelce, who was the best tight end in the league without Rob Gronkowski playing, as well as, hopefully, a healthy Jeremy Maclin. There are enough pieces in place to have this offense go over the top.

The issue is at quarterback, where Alex Smith, who, while both under-appreciated and efficient, does hold the Chiefs back. It’s not hard to imagine Kansas City as a possible landing spot for Tony Romo. Behind a quality offensive line (13th in pass blocking, 17th in run blocking for the season according to Pro Football Focus’ grades), Romo could wheel and deal to a multitude of weapons, serving as a more explosive triggerman in Reid’s offensive scheme.

Is Alex Smith capable of leading the Chiefs to the Super Bowl? USATSI

Reid has said this offseason that Smith is still the guy.

“I’m lucky enough to have Alex Smith, who I think is phenomenal and still can play,” Reid said. “I was asked that question like two seconds after the game and then it turned into, like, a controversy. He’s our quarterback, by the way, and he’s right here at the Pro Bowl so I think we’re going to keep him.”

But Reid waffled a bit immediately after the season when talking about Smith. Let’s not act like he won’t trade a quarterback if he thinks it’s time to move on. (Hello, Donovan McNabb.)

The weapons and protection are there on offense. The defense is largely going to be back, although the Chiefs need to quickly figure out how they’re going to handle the situation of Dontari Poe and Eric Berry. Both are unrestricted free agents, but there is only one franchise tag, and while Berry might be the easier candidate, he’s said he won’t play on the tag again this year.

An upgrade at quarterback, an early financial solution for Poe or Berry (allowing the other to be tagged) and the Chiefs will become a very popular pick to win it all in 2017.

This is the other popular destination thrown out for Romo. The Texans are similar to the Chiefs, but just in a much worse place at quarterback. The desperation from this organization should’ve been apparent last offseason, when it signed Brock Osweiler to a $72 million deal that might as well have been announced as a two-year, $35 million contract. There’s almost no way they won’t get out from under that deal as soon as humanly possible, and Osweiler could even become a very expensive victory cigar if the organization can upgrade enough this offseason.

The logic for being desperate makes even more sense this year, with all-world defensive end J.J. Watt coming off a year where he underwent multiple surgeries. Jadeveon Clowney is coming into his own and Whitney Mercilus (19.5 sacks the last two years) has become one of the most underrated defenders in the league. The window for having Watt, who is/was on pace to become one of the all-time great defensive players, feels much shorter now, even though he’s only 27.

J.J. Watt can’t win a title without a quarterback. USATSI

Vince Wilfork is likely walking away into retirement, and A.J. Bouye is starting to loom as a brutal loss because the Texans appear unlikely to use the franchise tag on the emerging cornerback. Houston has been reluctant throughout franchise history to use the tag (only using it once, on Dunta Robinson in 2009) and doesn’t have a ton of cap space with which to play. Having Johnathan Joseph, Kareem Jackson and Kevin Johnson all expected to be ready for 2017 helps the situation.

However, we can check the desperation level for Houston depending on what they do with Bouye. A team really trying to push all in would tag Bouye and hope to work out a deal with a low cap figure for 2017. Bring him back as part of the top-ranked defense from 2016, welcome Watt back, invest some picks in the offensive line and make a push for Romo. Romo throwing to DeAndre Hopkins and Will Fuller with Lamar Miller coming out of the backfield is a recipe for winning the AFC South again, only this time with a decent shot at winning a playoff game.

For the last two years, an NFC South team has made the Super Bowl and for the last two years, the only NFC South quarterback with a Super Bowl ring has been home watching. Drew Brees and the Saints are heading down the home stretch of a long and fruitful relationship -- regardless of what happens in the future. New Orleans will never forget Brees and the Saints bringing home a championship in 2009. But the reality is that title is a long way in the rearview mirror at this point; New Orleans made the playoffs three of the next four years after winning Super Bowl XLIV but finished with 7-9 records the last three seasons.

Sean Payton has been rumored to be heading elsewhere each of the last three offseasons (one of which included Payton walking around the owners’ meetings with a contract in his briefcase) but ultimately remained in New Orleans to give it one last go with Brees in 2017.

The Saints offense rarely slows down, and with the emergence of Michael Thomas as a rookie and Coby Fleener/Mark Ingram on the roster, Brees should put up eye-popping stats again this year.

Can Drew Brees deliver the Saints another shot at a title? Getty Images

But the defense has never been more desperate (or is always just as desperate) and the Saints have to figure out how to generate some pass rush and it is probably going to come from the draft or free agency. For the first time in a while, there is actually some interesting talent on defense for the Saints. Sheldon Rankins was sorely missed during his rookie season. Stephone Anthony should continue to improve. Delvin Breaux if healthy would make a huge difference.

This is a traditionally splash team that just saw its sister organization make a massive move for Boogie Cousins on the night of the All-Star Game in New Orleans. The Saints don’t have the capital to pull something like that off, per se, but there is some defensive talent that could hit the market. “Cap-strapped” isn’t a word that exists for a franchise that found a way to sign Jairus Byrd as a free agent even though it didn’t have any room.

We’d tell Mickey Loomis it was his move now, but he’s somehow running both franchises.

It’s hard for a team with two Super Bowl titles in the last decade to feel desperate, but the Giants should be aggressive again this offseason. 2016 was a surprise for the traditionally cost-conservative Giants, primarily because they went heavy in free-agent investments and it paid off in a big way for the franchise.

GM Jerry Reese took a rare, aggressive dip into free agency, signing Olivier Vernon, Janoris Jenkins and Damon Harrison to big-money contracts, while bringing back Jason Pierre-Paul. The result was a tremendous improvement on that side of the ball.

The offense, with Ben McAdoo moving from coordinator to head coach, took a step back. Eli Manning looked like he might be heading in the decline direction, and the line didn’t do a good job protecting him. Manning was only sacked 21 times, but he had his worst season since McAdoo arrived. Eli turned 36 in January, and there’s a minimal window to pursue another title with him on the roster.

Can Eli Manning get another ring before calling it a career? USATSI

Getting aggressive in free agency and the draft to protect Manning and secure additional defensive line help (Jason Pierre-Paul and Johnathan Hankins are both free agents) is critical.

It’s not a stretch at all to think Reese could survey the landscape, look at his cap space ($30M+, thanks to an expected jump in the cap number this season) and think about diving back into free agency. It worked last year, why can’t it work again? That might be a fallacy, but with a team holding a likely Hall of Fame quarterback coming off a first-round shellacking in the playoffs, it’s not crazy to expect some strong offseason moves.

Los Angeles Chargers

Based on recent drafting and player acquisition, the Chargers are actually built pretty decently for the future. Melvin Gordon and Keenan Allen are young core pieces on offense, even if injuries are a concern with both guys. Hunter Henry could end up being a stud as well. Joey Bosa, Jason Verrett and Denzel Perryman form a nice core on the other side.

But the culmination of two huge factors make the new-look Chargers a win-now team.

First there’s the new look (no, not the disastrous logo change): moving to Los Angeles. A move of a franchise usually only happens if that franchise isn’t winning, but it’s not mutually exclusive. When the move happens, however, winning early is critical. This is especially important with the Chargers, because they’re moving somewhere without a built-in fanbase and somewhere where there’s already another NFL team. The Rams are ripe to have fans stolen, but the Chargers can’t do it by being mediocre. Ownership will want a quick return on the move.

And secondly, there’s the quarterback. Philip Rivers, who like Eli Manning, has a limited window. (You could also lump Ben Roethlisberger in here as well.) He’s a 36-year-old quarterback who’s still playing, at times, MVP-caliber football and elevating people around him. The pressure is lessened on Rivers this season with the Chargers officially moved, but the timeline for him playing football has shrunk.

Philip Rivers is running out of time to win a Super Bowl. USATSI

Tom Telesco just fired Mike McCoy and brought along new coach Anthony Lynn. Even though Lynn has no head coaching experience -- and limited coordinating experience -- the leash for improvement over the past few years can’t be that long. The roster is too talented.

San Diego is a few solid draft picks and one free agency home run (they hit one last year with Casey Hayward) from being capable of winning its division. Telesco won’t burn the future for a run now, but he should strongly consider putting a bunch of chips in the middle of the table and trying to win now while Rivers is on the roster.