WEST PALM BEACH, Fla. - Though the Nationals are interested in signing Craig Kimbrel, they must overcome a significant hurdle before inking a deal with the free agent closer.

Sources have confirmed that the Nationals front office would like to add Kimbrel to serve as their ninth-inning arm, but such a move would require ownership approval because a contract would eclipse the luxury tax threshold. So far, ownership is unwilling to exceed the luxury tax for a third consecutive season, the sources said.

Kimbrel, 30, entered the offseason as the top reliever on the free agent market, and was said to be seeking a six-year deal in excess of $100 million. However, three weeks into spring training, he remains on the open market, and agent David Meter has been unable to reach an agreement as possible suitors have dwindled.

The right-hander went 5-1 with a 2.74 ERA and 42 saves in 47 chances for the Red Sox last year, but his ERA increased by more than a run from his 1.43 mark the previous season, his walks/nine innings went up from 1.8 to 4.5 and his strikeouts/nine innings decreased from 16.4 to 13.9.

In nine postseason outings for the World Series champions, he recorded six saves, but was far less dominant than usual. He posted a 5.90 ERA and a 1.59 WHIP.

The Nationals currently sit about $4.5 million below the $206 million luxury tax threshold. If they exceed that figure for a third consecutive season, they would be required to pay a 50 percent tax on every dollar they spend over the limit. In addition, the Nats would forfeit their third- and sixth-round picks in the 2019 First-Year Player Draft if they signed Kimbrel; they previously lost their second- and fifth-round selections for signing free agent starting pitcher Patrick Corbin to a six-year, $140 million deal.

However, last year’s penalty for exceeding the luxury tax amounted to about $2.4 million, and while that seems like a small amount for a contending team, Nationals ownership seems to prefer resetting the penalties by coming in under the $206 million figure.

The addition of Kimbrel would change the constitution of the Nationals bullpen. With Kimbrel closing games, incumbent closer Sean Doolittle would slide into the eighth inning, while newcomer Trevor Rosenthal could pitch the seventh inning.

General manager Mike Rizzo is of the belief that strong teams must always seek ways to get stronger, and though the bullpen looms as a potential strength, Doolittle missed three months with a toe injury last season, Rosenthal is coming off Tommy John surgery that cost him all of the 2018 season and trade acquisition Kyle Barraclough dealt with a right shoulder injury in 2017. In addition, right-hander Koda Glover has been sidelined with right forearm strain and Justin Miller has been battling a sore back early in camp.