Manuel Balce Ceneta/AP

The deadline to tender contracts to players eligible for arbitration comes Friday at 11:59 p.m., and this year it could mean the Nationals part ways with two of their longest tenured players.

The Nationals are expected to non-tender both starter John Lannan and catcher Jesus Flores, both of whom made their major league debuts for the Nationals in 2009. They could also try to trade either one before the deadline arrives.

The Nationals have eight other players who are eligible for arbitration, and they seem likely to tender all of them contracts for 2013. The rash of arbitration-eligible Nationals speaks to one issue for the Nationals now and in coming seasons: Their own core players will begin to become more and more expensive, which will be a factor to consider in any free agent shopping.

Here’s a rundown of the Nationals’ 10 arbitration-eligible players.

Likely Non-Tenders

SP John Lannan: The expectation remains Lannan will be non-tendered and free to catch on with another team. His sinkerball style goes against the power-armed prototype Mike Rizzo prefers, and he does not seem to fit into the Nationals’ plans, even though he’s been a proven starter, he’ll make about $5 million this year and they need a fifth starter to replace free agent Edwin Jackson. Lannan, who through no fault of his own spent most of 2012 at Class AAA Syracuse, has a career 103 ERA+. Lannan is a fine pitcher and he’s not making a big salary. The Nationals, it seems, think they can do better.

C Jesus Flores: In Wilson Ramos and Kurt Suzuki, the Nationals have two catchers worthy of playing every day, even if one of them is coming off of an ACL injury. They also have two catchers, in Jhonatan Solano and Sandy Leon, who could fill as a third catcher if needed. Flores hit .213 and, with little help from the Nationals’ pitching staff, threw out 15 percent of the runners who tried to steal against him. After a disappointing season at the plate and in the field, Flores will still catch on in the majors. But after six seasons with the Nationals, it won’t be here any longer.

Final Year or Arbitration

RP Tom Gorzelanny: The Nationals will need another left-hander if they lose Sean Burnett in free agency, and Gorzelanny, mostly a long reliever, was productive and versatile out of the bullpen last year. The Nationals have gotten good mileage out of the trade that brought Gorzelanny here: They shipped him to the Cubs for minor league outfielder Michael Burgess and minor league pitchers A.J. Morris and Graham Hicks. Burgess, 23, hasn’t advanced past Class AA, Morris is 25 and in High A and Hicks is back with the Nationals.

Second Year

SP Jordan Zimmermann (Super Two): The Nationals kicked around the idea of a long-term extension with Zimmermann early in 2012, but the talks never really went anywhere. He is a clear piece of the Nationals’ core, and now that he’s entering his second (of four) years of arbitration, the Nationals may want to get those talks going again.

RP Tyler Clippard (Super Two): Given the large salaries doled out to relievers this winter already, Clippard looks like a great trade chip considering he’ll likely get a raise to around $4.5 million for one year. But it also makes him valuable to the Nationals. They’ll likely be losing Sean Burnett, and Clippard, thanks to his changeup, has been great against lefties. Left-handed batters hit .170/.260/.259 off Clippard last year.

First Year

SS Ian Desmond: Desmond may have been as responsible as any one player for the Nationals’ improvement in 2012. His performance was worth 1.4 wins above replacement in 2011, per FanGraphs, and it jumped to 5.4 in 2012. Gaining four wins by simply running out the same player, making the same salary, is quite a boon. Desmond will be rewarded in arbitration, and the Nationals could consider a long-term deal with him.

RP Drew Storen (Super Two): Storen’s decision to sign immediately after the Nationals chose him with the 10th pick in 2009 has worked out well for him. He reached the majors just in time to qualify for Super Two status, which is why he’s eligible for arbitration now. Only four players chosen in the 2009 first round have more career WAR (per Baseball-Reference) than Storen: Mike Trout (25th overall), Dustin Ackley (2nd), Stephen Strasburg (1st) and Mike Leake (8th). He has a slight edge over Royals right-hander Aaron Crow, who was picked 12th in 2009 – the year after the Nationals picked him ninth but could not sign him, putting them in position to draft Storen.

SP Ross Detwiler: It seems hard to believe now that Detwiler spent three turns through the rotation in the bullpen behind Chien-Ming Wang. Had the Nationals won Game 5, Detwiler was shaping up to be a breakout star of the postseason, a la Madison Bumgarner a couple years ago. As of last check, the Nationals hadn’t initiated any extension talks. One full season like his second half, and Detwiler will start to get awfully expensive.

OF Roger Bernadina: No one has been with the franchise longer than Bernadina, who signed with the Expos out of Curacao in 2001. He could maybe get a chance to play every day on a bottom-feeding team, but the Nationals will be happy to bring him back as a backup after his best season.

RP Craig Stammen: After three up-and-down seasons as a starter, Stammen found a permanent place in the majors this season out of the bullpen. He was durable enough to pitch multiple innings at a time and dominant enough to set up when needed. He looked like a fringe piece in spring training last year, and now he looks like established part of the Nationals’ bullpen.