Quarterback stability is highly coveted in the NFL because it's a vital ingredient for sustained success. Some of the NFL's most significant transactions occur in an effort to get the position settled.

The 49ers made an unexpected move at the October 31 trading deadline by acquiring Jimmy Garoppolo, whose rookie contract expires after the season, from the Patriots for a 2018 second-round pick. Garoppolo has yet to make his 49ers debut because he's been focused on learning the 49ers offense. There isn't a set timetable for Garoppolo to play. Garoppolo is a prime candidate for a franchise tag, which is expected to be in the $23 million to $24 million neighborhood, if a new deal isn't in place by early March.

Demand is usually much greater than the supply of desirable quarterbacks typically available in the offseason, but 2018 may be one of the rare instances where this isn't the case.

Here's a look at the passers who could be on the quarterback carousel in the offseason:

Drew Brees QB / Saints

Brees recently reiterated his desire to finish his career in New Orleans although he is going to play out his contract, a one-year extension for $24.25 million signed early in the 2016 season. The Saints no longer have to rely on Brees' passing for success because of one of the NFL's most potent rushing attacks and a perpetually weak pass defense that has been fixed. Brees is on pace to throw for under 4,500 yards for the first time since 2009. The 38-year-old demonstrated that he is still capable of winning games with his arm in an improbable Week 11 come-from-behind overtime victory against the Redskins.

Brees' contract was structured with 2018 through 2020 contract years that automatically void on March 14, the last day of the 2017 league year. This voiding date eliminates the possibility of Brees being given a franchise tag since it is after the designation period ends on March 6. If an extension isn't worked out between the end of the season and the voiding date, the Saints will have an $18 million salary cap charge in 2018 regardless of where Brees plays next year because of the proration from the $30 million signing bonus he received with his 2016 extension.

It may make sense for Brees and the Saints to go year-to-year since Father Time is undefeated. The 2018 money could be converted into a real contract where the voiding of the 2019 and 2020 contract year is delayed until the last day of the 2018 league year in March 2019.

There isn't anything in Brees' history to suggest that he would give the Saints a hometown discount. His current contract made him the NFL's second highest-paid player by average yearly salary when signed. Regaining that place in the league's salary hierarchy would likely mean a one-year deal for 2018 in the neighborhood of $26.5 million.

Eli Manning QB / Giants

Expected to contend for the NFC East title, the Giants appear to be destined for a top five pick in the 2018 NFL Draft. Wholesale changes (front office, coaching, personnel) may be on the horizon. Manning spending his entire career with the Giants could be in jeopardy because of the disappointing season. Landing a high pick would put the Giants in position to find Manning's successor. The Giants can't deal Manning to another team without his permission since he has a no-trade clause in his contract, which runs through the 2019 season. The Jaguars have been most frequently mentioned as a potential destination for Manning because his former head coach Tom Coughlin is Jacksonville's executive vice president of football operations.

Kirk Cousins QB / Redskins

Designated as a franchise player for a second straight year, Cousins is playing the 2017 season for a fully guaranteed $23,943,600 because he rejected a Redskins offer reportedly worth $133 million over six years. This offer contained $72 million in overall guarantees, of which $53 million was fully guaranteed at signing. Under franchise tag rules, the Redskins are prohibited from signing Cousins to a multi-year contract until the end of the 2017 regular season on December 31.

Redskins president Bruce Allen has indicated that designating Cousins as a franchise player in 2018 for a third and final time at almost $34.5 million is a possibility despite the steep cost. Receiving another franchise tag will make continuing to go year-to-year before hitting free agency in 2019 extremely attractive unless the Redskins are willing to make him the NFL's highest-paid player over Lions quarterback Matthew Stafford, who signed a five-year, $135 million contract extension with an NFL record $92 million of overall guarantees during the preseason. Another option is using a transition tag for $28,732,320, which would only give the Redskins a right to match another team's offer sheet.

Cousins could be a litmus for quarterback salaries should he become an unrestricted free agent because quality passers in their prime almost never hit the open market. He is performing like he did during the 2015 and 2016 seasons when he was one of the NFL's most productive quarterbacks statistically despite a higher degree of difficulty this time around. The Redskins' offensive line has been decimated by injuries. Cousins' rapport with the wide receivers isn't nearly as good with DeSean Jackson and Pierre Garcon signing with the Buccaneers and 49ers in free agency. Additionally, he has had to adjust to a new play-caller with Sean McVay becoming a head coach of the year candidate for his quick turnaround of the Rams. Nonetheless, Cousins is on track for his third straight season with at least 4,000 passing yards, 25 or more touchdown passes, a top-10 completion percentage and a touchdown- to-interception ratio greater than two-to-one.
It's conceivable that Cousins could command $30 million per year with $100 million in guarantees on the open market because there are more NFL teams than competent quarterbacks. Some of the quarterback-needy teams, such as the Browns and Jets, will have an abundance of cap space next offseason.

Alex Smith QB / Chiefs

The Chiefs trading up to use the 10th overall pick in this year's draft on Patrick Mahomes put Smith on notice. A 5-0 start with Smith looking like an MVP candidate ended speculation that this season would be his last in Kansas City. The Chiefs dropping to a 6-4 record not only renewed talk that Smith's days in Kansas City are numbered but has some clamoring for Mahomes to take over at quarterback now. Missing the playoffs entirely or another early exit will likely result in the transition from Smith to Mahomes taking place next year. Financially, it makes sense for the Chiefs to move on from Smith's four-year, $68 million extension, which expires after the 2018 season, in the offseason. The Chiefs have the NFL's fourth most 2018 salary cap commitments at slightly over $179.5 million with a little more than $3.5 million of cap space that can be carried over to next year. Trading or releasing Smith, would in 2018, net the Chiefs $17 million in cap room.

Sam Bradford QB / Vikings

Bradford was probably going to be in an enviable position with good health. A contract similar to Derek Carr's ($25 million per year with $70 million in overall guarantees) as a free agent would have been a possibility provided he could have can maintained or improved upon his 2016 performance. In 2016, Bradford set an NFL single season record with a 71.6 completion percentage and threw for a career high 3,877 yards while getting comfortable with Minnesota's offense on the fly after a surprising trade from the Eagles in the days leading up to the regular season opener.