Brandon Kintzler uses a biting sinker to get ground balls on demand. (Katherine Frey/The Washington Post)

LAKE BUENA VISTA, Fla. — Early Thursday morning, as the bars at the Dolphin and Swan cleared out and baseball’s winter meetings slid slowly toward a close, the Nationals agreed to a deal with right-handed reliever Brandon Kintzler, according to a person familiar with the situation. The deal can be worth up to $15 million over the next two seasons, with Kintzler due $5 million in 2018. If he meets incentives, the club option that would make the deal worth $15 million over two seasons kicks in. If he doesn’t, or if he gets hurt and cannot earn those incentives, Kintzler has a player option worth $5 million that would guarantee him another season in D.C. to recoup his value, meaning he is guaranteed $10 million, according to people familiar with the deal.

The agreement came after midnight, after a few days of conversations and a run on relievers that left the Nationals with a dwindling list of options to fill their glaring need for right-handed middle relief. As it happened, they decided to bring back a familiar face, the former Minnesota Twins closer they acquired at last year’s trade deadline and slotted into a seventh-inning role ahead of Ryan Madson and Sean Doolittle.

Other teams expressed interest in Kintzler to serve as their closer, but the 33-year-old chose the Nationals, where he found a comfortable clubhouse and a chance to win when he arrived in July. Doolittle and fellow Las Vegas resident Bryce Harper reached out to Kintzler, encouraging him to return to D.C. if he could. Their pleas, combined with Kintzler’s willingness to take an unorthodox deal that forces him to prove he deserves the kind of money less accomplished relievers are earning this week, brought the right-hander back to the Nationals in the end.

Kintzler’s case is a telling study of the state of the free agent relief market. Advanced metrics are not kind to him, which hurts his market value. He relies less on swings and misses than nearly all late-inning relief types, instead utilizing a biting sinker to get ground balls on demand. He finished last season with a 3.03 ERA in 72 appearances, 27 of which came with the Nationals, who found him most successful when given a full inning of work as opposed to when used for the kind of mid-inning firefighting many sinker-heavy types endure. He will likely return to seventh-inning duties this season.

The Nationals’ urgency to add a proven righty to handle the middle-to-later innings grew as the free agent reliever market began to move, then accelerated, this week. In the process, the pool of available relievers shrank quickly, with a caveat: The moves have revealed this year’s reliever market as an expensive place to shop. As the supply decreased, demand did, too, and the Nationals suddenly seemed likely to have to spend exorbitantly to secure the help they needed.

Among the more talked-about signings this week was the Philadelphia Phillies’ deal with right-hander Tommy Hunter, who will make $18 million over two seasons. Hunter was not considered one of the top relievers available — not nearly on the level of say, right-hander Brandon Morrow — but will make just $2 million less annually than Morrow will to close for the Chicago Cubs. Pat Neshek, an all-star last season, signed for two years and $16 million. Veteran Luke Gregerson signed for two years and $11 million. For reference, when Shawn Kelley signed his three-year deal worth $15 million two offseasons ago, heads not only turned, but snapped in surprise. Now, a man who pitched the sixth inning for a non-contender last season (Hunter) will make $9 million a year.

Hunter’s deal set an impossible precedent for both agents and teams. If Hunter was worth $9 million, what would someone with 29 saves (like Kintzler) be worth? And how could an agent justify getting his client less? Then again, if Hunter was worth $9 million, how could a team afford a more proven arm like Kintzler’s at any reasonable price? As the market continued to move Wednesday, that Hunter deal began to look more like an outlier than the norm. Still, that the Nationals got Kintzler for such a reasonable price represents an encouraging start to their offseason.

The deal also makes sense for Kintzler, who can ultimately earn a two-year deal worth $15 million by turning in a solid 2018 season. Two years and $15 million is just about what Neshek got, which feels about right for a man who recorded 29 saves in a few months of closing duty before a deadline deal. But in taking that deal, Kintzler bet on himself to earn market value, rather than settling for a lesser sure thing.

Nationals General Manager Mike Rizzo has said the team will not be restricted in their spending this winter despite crossing the competitive balance tax threshold last season. They are already projected to threaten it again next season. But the Nationals cannot afford to throw money at relievers like the Phillies can, or won’t be tossing out three years and an option to Jake McGee like the Colorado Rockies did, as Rizzo is always hesitant to sign relievers to long-term contracts. Kelley’s three-year deal was one of the longest for a reliever in his tenure.

The sense around agents representing relievers is that the Nationals think highly of Wade Davis, but that the price tag — which many estimate to be around four years and $60 million, or something close to what Mark Melancon got from the San Francisco Giants last offseason — might be too high for them. Another man likely to command late-inning money and push for a longer deal, right-hander Addison Reed, is also still available. The Nationals have expressed interest in him and might find his price tag slightly more manageable. Whether they still remain interested in bigger names like those after signing Kintzler is currently unclear.

The Nationals also talked about bringing back Matt Albers, according to a person familiar with the situation, but ultimately decided on Kintzler instead. They have also checked in on bounce-back candidate Hector Rondon, who emerged as a middle-innings stalwart with the Cubs before falling off and earning a non-tender this season.

Rizzo has said repeatedly that he is more than comfortable with the lefties he has in the bullpen, namely Sammy Solis and Enny Romero. But Solis has struggled in October for two straight seasons, and Romero has no history of big game success or failure. While Rizzo maintains his priority is right-handed relief, he could still be talked into pivoting toward a more proven left-hander at a manageable price. Tony Watson and Boone Logan are among those lefties available.

But Kintzler joins Madson as one of the few right-handed sure things for the Nationals, who expect Koda Glover to be 100 percent for spring training and are hoping for the same for Shawn Kelley. Glover, who was shut down with rotator cuff trouble last season, is already throwing again and is on track to begin spring training uninhibited. Kelley did not need surgery on the elbow that forced his season to end prematurely, but has had two Tommy John surgeries and is therefore no sure thing to bounce back from his trying 2017 season.

Rizzo prioritized right-handed relief help this week in large part due to the questionable status of Glover and Kelley. The Nationals currently have Kintzler, Madson, Kelley, Glover, Trevor Gott and Austin Adams as right-handed relievers with major league experience on their roster. Wander Suero might have a chance to make the team out of spring training, and already has a roster spot, but is unproven. Right-hander Jefry Rodriguez, also afforded a roster spot this winter, has never pitched above Class A Potomac. They are not set from the right side, but can now peruse the market for value, rather than sure things. As with Albers last year or Matt Belisle in 2016, the Nationals have shown themselves capable of finding steady middle relievers late in the offseason by signing veterans to minor league deals and inviting them to spring training.

For now, Rizzo and his staff can fly to D.C. with a weight off their shoulders, less burdened by the stresses of the billowing relief market. They have the seventh, eighth and ninth taken care of, which is more than they can usually say at this time of year.

Read more on the Nationals:

Nationals confirm ‘preliminary conversation’ on Bryce Harper contract extension

Nationals won’t admit they need to, but here’s how they could improve at catcher

Could Jake Arrieta, another high-priced Scott Boras client, be destined for the Nationals?

After getting valuable bench play last season, Nationals have some holes to fill

New Nationals Manager Dave Martinez shows he can talk a good game