Where will Kirk Cousins play next season? (AP Photo/Mark Tenally)

Sunday afternoon, Kirk Cousins will run out of the tunnel as the Washington Redskins’ starting quarterback for the 28th and, most likely, last time at FedEx Field. The union between Cousins and the Redskins has been dissected and debated for more than three years, and it is about to reach its likely denouement in a half-empty stadium, with a game irrelevant to the NFL standings.

“I’ve had multiple years here where it was the final year of my contract, so I guess those possibilities have come up before,” Cousins said Wednesday. “I guess now that it’s been the third go around of that, you just kind of go out and play and let the chips fall where they may.”

The Redskins have, depending on interpretation, declined or failed to sign Cousins to a long-term contract, leaving them in the rare position of either using a third consecutive franchise tag to pay a prohibitive, unprecedented one-year salary or let a consensus franchise quarterback walk away for nothing. The Redskins could still reverse course and sign Cousins or use the transition tag to keep him at roughly $28 million for one season or match offer sheets from other teams. But it has become a widely held assumption Cousins will play elsewhere next season.

The operative question, then, is where? The teams that seemed to be Cousins’s most logical destinations at the start of the season have found stable solutions at quarterback. Four teams are likely to pick a first-round quarterback this year, joining the five that did so in the past two years. Plenty of teams, especially playoff-ready teams Cousins would find appealing, have their quarterback in place for 2018, if not beyond.

But just because the complexion of the market has shifted does not mean the demand for Cousins will wane this offseason. It takes only two teams to build a free-agent market, and the NFL has more than two teams seeking a long-term answer at quarterback that would prefer not to wait for a rookie to develop.

Cousins may not land with a team many expected he would, and he would enter free agency having lost the only playoff game he’s ever started. But he will find a market eager to pay top dollar for a 29-year-old who has completed 67.7 percent of his passes at 7.9 yards per attempt the past three seasons.

“When was the last time a marquee quarterback went to free agency?” said one NFL agent, who requested anonymity to speak freely about another agent’s client. “I think somebody will give him $27 million a year. Kirk is going to get paid. Somebody is going to overpay more than you ever dreamed, because they really think he’s the answer.”

Should Cousins reach free agency, it would mark an effectively unprecedented scenario in recent NFL history — a healthy quarterback, entering his age-30 season, coming off a 4,000-yard season, available to the highest bidder. Peyton Manning became a free agent in his late 30s, coming off neck fusion surgery. Drew Brees decided between Miami and New Orleans back in 2006 after shoulder surgery.

“It never happens,” said former Tampa Bay Buccaneers General Manager Mark Dominik, now a Sirius XM radio host. “It just doesn’t happen. The only time it happens is if a quarterback is coming off an injury.”

Once teams have even viable quarterbacks, they don’t let them get away for nothing. The opening week of this season, only six starting quarterbacks joined their team via free agency:

-Tyrod Taylor, who had never started a game before he joined Buffalo before the 2014 season.

-Josh McCown, a 38-year-old signed this offseason who had gone 2-20 as a starter in his past three seasons.

-Mike Glennon, whom the Bears signed to a three-year, $45 million deal despite not starting for Tampa Bay the year before.

-Brian Hoyer, who had played for four teams in five years before the 49ers signed him last season.

-Jay Cutler, who came out of retirement only after Ryan Tannehill suffered a season-ending injury in preseason.

-Drew Brees, who signed with the Saints in 2006 after undergoing shoulder surgery.

The combination of Cousins’s statistical track record and the league’s desperation for quarterbacks will mean a high price tag. Last year, Mike Glennon received a three-year, $45 million contract in free agency from the Chicago Bears, who immediately traded up to draft Mitchell Trubisky with the second overall pick, anyway.

“If you ask a team like New England, they would tell you you can sign one, because they’ve had one,” an AFC executive said. “If you ask that question of someone like Cleveland or the Jets the last few years, they’re dying for one.”

Entering the season, the franchises most-speculated as destinations for Cousins were the San Francisco 49ers and Los Angeles Rams. Both teams had been taken over by new head coaches — Kyle Shanahan and Sean McVay — who once served as Cousins’s offensive coordinator in Washington and were avowed believers in him. Neither team had a clear franchise quarterback, with San Francisco having moved on from Colin Kaepernick and the Rams unsure of 2016 first overall pick Jared Goff after a rocky rookie year.

The events of the season, though, turned two likely suitors for Cousins into two of the more stable quarterback situations in the league. Under McVay, Goff transformed into one of the NFL’s most efficient passers, responding to McVay’s savvy coaching and brilliant game-planning. The 49ers swung a surprise trade for former New England backup Jimmy Garoppolo, who in a handful of starts has already established himself as a piece of San Francisco’s bedrock.

So the shape of the market changed — but not the demand. Plenty of teams will bid for Cousins at eye-popping figures, starting, perhaps with the Redskins’ opponent Sunday.

The Denver Broncos will miss the playoffs for the second consecutive season, and their quarterback troika — Trevor Siemian, Paxton Lynch and Brock Osweiler — proved hopeless this season. John Elway is not a personnel head who believes in rebuilding, and Cousins’s agent, Mike McCartney, is viewed inside the league as having a strong relationship to Denver’s management.

“John, he’s not going to mess around,” Dominik said. “He’s went and got a veteran quarterback before, and he’s going to want to do it again. Denver is a very logical spot.”

The Arizona Cardinals can get out of Carson Palmer’s contract this offseason at minimal cost, if Palmer decides he wants to return at age 39. Dominik suggested both New York teams would be in position to draft a future quarterback, but one, particularly the Jets, would rather not wait.

While possible landing spots pile up, the NFL’s salary cap is expected to increase between roughly $8 million and $10 million, an inflation that would also balloon Cousins’s contract. Even if Cousins doesn’t get a deal worth $27 million a year, it will probably land in the range of $24 million to $26 million.

“I see there being a market for him,” Dominik said. “If you sit there and say, you can’t pay him top-10 or top-five money, that’s not the way the league is headed. He’s the first one to eat at the new table, so he gets the biggest bite.”

One stealth possibility, based on dot-connecting: The Pittsburgh Steelers. Ben Roethlisberger has openly contemplated retirement the past two offseasons. The Steelers have an offense built around Le’Veon Bell and Antonio Brown, which means they can expect to contend. Steelers Coach Mike Tomlin was the only NFL head coach who attended Cousins’s pro day at Michigan State, and the pair have maintained an informal relationship over the years. Cousins also played two seasons with Bell in college. Cousins has expressed a desire for organizational stability and annual contention, two qualities the Steelers are known for.

For Cousins’s sake, as long as the field of competitors for his services numbers at least two, he will become one of the highest paid players in the league.

“It’s going to take two legitimate teams to get him to 26, 27 [million per season],” Dominik said. “It seems like a lot when you think about, he hasn’t won a playoff game. I challenge teams that have been without a quarterback to see how hard it is in this league to play without one. When you don’t have one, you can’t sustain a franchise without a quarterback.”

The Redskins may soon find out. They will watch Cousins play in their home stadium Sunday, maybe for one final time. Or maybe not. Cousins and the Skins seem unlikely to come to a deal. The transition tag remains a possibility — Cousins would earn about $28 million for one season, with opposing teams able to offer him a multiyear contract, but with the Redskins holding the right to match. If they didn’t match and Cousins left, Washington would receive no compensation.

In the end, Washington will probably be looking for a new quarterback. But as teams line up to pursue Cousins, nothing is determined.

“I’ve learned one thing in this business,” the agent said. “There’s nothing impossible, because everybody in this business is crazy.”

>>> The Rams’s Super Bowl hopes hit an unexpected snag. Kicker Greg Zuerlein was placed on injured reserve, ESPN’s Adam Schefter reports. They signed Sam Ficken to replace him. Zuerlein might be the best kicker in the NFL, although Justin Tucker would have something to say about it. Zuerlein has been a major part of the 10-4 Rams’ success. Los Angeles, per Pro Football Focus, has had far and away the best special teams in the NFL this season. Zuerlein was a weapon, in both kicking field goals (38 for 40) and pinning teams deep with kickoffs.

>>> The Giants interviewed Dave Gettleman for their vacant general manager position, Paul Schwartz writes. Gettleman appears to be the Giants’ top choice. Gettleman worked for the Giants for 15 years and helped the Carolina Panthers’s NFC title team. The downside is, Gettleman is 67, so he wouldn’t be growing into the job for a long tenure.