A financial breakdown of the Nationals’ upcoming offseason

Barring unexpected seismic offseason activity, the Nationals’ core will remain intact for 2017. That core claimed the National League East title with 95 victories to advance to the club’s third postseason in five years. It’s one of the best cores in baseball.

This winter, therefore, is about tinkering around the foundation. Washington has eight impending free agents and two players with club options for 2017. Six other players are eligible for arbitration — it was seven until the team placed Aaron Barrett on waivers Monday — and the Nationals have until Dec. 2 to tender contracts to them.

Before we dive into the moving parts, some background on the Nationals’ recent fiscal history. Washington’s 25-man opening day payroll in 2016 was $145,178,886, which was a drop from the $162,014,559 on the books in 2015. A return to the 2015 neighborhood is possible, though splurging much beyond that is unlikely. As the roster currently stands, Washington has $97,547,333 in contracts for 2017, excluding players with club options, pre-arbitration players and arbitration players.

Add pre-arbitration players expected to make the opening day roster next season — we’ll go with Trea Turner, Joe Ross, Sammy Solis, Blake Treinen and Clint Robinson — and the payroll increases to a bit over $100 million. Other pre-arbitration players on the 40-man roster that could make the club include Pedro Severino, Reynaldo Lopez, Koda Glover, Brian Goodwin, Wilmer Difo and Michael A. Taylor.

Wilson Ramos and Mark Melancon highlight the Nationals’ cluster of free agents, which also includes Stephen Drew, Chris Heisey, Marc Rzepczynski, Sean Burnett, Matt Belisle and Mat Latos. Ramos made $5.35 million in his final year of arbitration and was en route to a big payday until a torn anterior cruciate ligament torpedoed his earnings potential. Melancon will draw suitors around the league as the third-best reliever on the market — after Aroldis Chapman and Kenley Jansen — following a fourth straight season as one of baseball’s best bullpen arms. The Nationals can extend a one-year, $17.2 million qualifying offer to Ramos, but not to Melancon because he was acquired midseason. Melancon made $9.65 million in 2016.

The only other position-player free agents are Drew and Heisey, two players on one-year deals that garnered praise throughout the season in their bench roles. Drew made $3 million as the club’s utility infielder and recorded a hefty .864 on-base-plus-slugging percentage in 165 plate appearances. Drew, who turns 34 in March, was nearly lost for the season after a bout with vertigo, but returned in September and was on the postseason roster. Drew’s veteran presence and bat was valued, but the Nationals could choose to go with Difo, a more economical choice, as their utility infielder off the bench in 2017.

Heisey signed for $1.25 million after making $2.16 million with the Dodgers in 2015. He played all three outfield positions and supplied pinch-hit pop, slugging nine home runs in 155 plate appearances during the regular season. He added a pinch-hit two-run home run in Game 5 of the National League Division Series. Goodwin and Taylor are other feasible internal outfield options off the bench.

Gio Gonzalez and Yusmeiro Petit have club options for next season. Gonzalez’s option is for $12 million with a $500,000 buyout. Gonzalez’s was inconsistent and registered his highest ERA (4.57) since breaking into the majors in 2008, but $12 million for a durable 31-year-old left-handed starting pitcher is a sound investment, which could also make him an enticing trade chip because of the weak starting pitching crop in free agency this winter. If the Nationals exercise the option, Gonzalez has a vesting option of $12 million for 2018 that he would secure by logging 180 innings in 2017. Gonzalez hasn’t broken the 180-inning barrier since 2013.

Petit’s option is for $3 million with a $500,000 buyout. The right-hander, who turns 32 next month, was in the Nationals’ bullpen all season, but was hardly used in the second half and finished with a 4.50 ERA in 62 innings.

The Nationals’ six arbitration-eligible players are Bryce Harper, Anthony Rendon, Tanner Roark, Danny Espinosa, Jose Lobaton and Ben Revere. Below are the players’ projected salaries if they are to go through arbitration, according to MLB Trade Rumors.

Harper: $9.3 million

Rendon: $6.4 million

Revere: $6.3 million

Roark: $6.1 million

Espinosa: $5.3 million

Lobaton: $1.6 million

Total: $35 million

Harper, Rendon, Roark and Espinosa are locks to return at those suppressed prices if deals aren’t struck before arbitration. Lobaton’s chances figure to have increased with Ramos’s injury because Severino is the only other major league ready catcher in the organization. Lobaton is well liked in the clubhouse and regularly draws accolades from pitchers for his defensive and game-calling abilities.

Washington, of course, could re-sign Ramos, but Ramos won’t be ready for the start of next season and mobility after a second ACL surgery on his right knee could be a concern. He’ll come much cheaper than projected before the injury, but the Nationals must weigh the risk. The Nationals could also sign another catcher, trade for one or roll with Severino and Lobaton in 2017.

Revere is the most likely to get non-tendered of the six arbitration-eligible players. The center fielder’s season was derailed before it started when he strained an oblique on opening day. He ended up posting the lowest on-base-plus-slugging percentage in baseball among players with at least 350 plate appearances and losing his spot to a rookie who had never played in the outfield as a professional before June. With Turner’s conversion, Goodwin’s late-season emergence and Taylor, the Nationals have cheaper alternatives available — if they don’t target a center fielder in free agency or via trade.

More from The Post: Nationals positional review series

Part I: The starting rotation

Part II: The bullpen

Part III: The infield

Part IV: The outfield

Part V: The catchers

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