Brandon Kintzler is a free agent. (Katherine Frey/The Washington Post)

A year ago, securing a closer was at the top of the Nationals’ offseason checklist. They tried. They offered a contract to Mark Melancon and, when Melancon rejected the deal, offered one to Kenley Jansen. He also declined Washington’s overture, leaving the Nationals scrambling with unproven in-house options. Blake Treinen was ultimately given the job. A three-and-a-half-month disaster ensued and a midseason bullpen overhaul was required to stabilize the relief corps. It included trading Treinen.

Washington doesn’t face that pressure this time around. The Nationals have Sean Doolittle and Ryan Madson, mid-July acquisitions from the Athletics, to populate the back end of their bullpen in 2018. They are proven, dependable and relatively cheap — Madson is on the books for $7.66 million and Doolittle for $4.38 million. The rest of the bullpen, however, is in flux.

Four of the Nationals’ 12 free agents this offseason are relievers. They are all at least 33 years old. Three — Brandon Kintzler, Matt Albers and Oliver Perez — were on their playoff roster. The other — Joe Blanton — was on the Opening Day roster. Most, if not all, probably won’t return. Bullpen turnover is commonplace.

“The bullpen is something that we’re going to really keep our eye on,” Nationals General Manager Mike Rizzo said in an interview on 106.7 The Fan on Wednesday. “And do our due diligence on and see if we can bolster that beyond what it is already.”

Doolittle, Madson, Enny Romero and Sammy Solis are the four relievers from Washington’s postseason bullpen under contract for next season. Austin Adams and Matt Grace finished the regular season with the club. Shawn Kelley, Koda Glover and Trevor Gott, all of whom finished the season on the disabled list, are also in the picture, as is Wander Suero. The 26-year-old right-hander hasn’t reached the majors, but compiled a 1.70 ERA in 42 1/3 innings for Class AAA Syracuse in 2017. The Nationals added him to their 40-man roster last week.

Kintzler is the most notable of Washington’s free agents. The right-hander ascended from independent leaguer to all-star closer for the Twins this season before Minnesota flipped him to Washington minutes before the July 31 nonwaiver trade deadline. Kintzler was assigned the seventh inning in front of Madson and allowed one run in 11 appearances in that frame. He struggled when dropped into other situations.

Every year, MLB Trade Rumors compiles a list of baseball’s 50 top free agents predicting where they will land. Kintzler is the only one the website projects will sign with the Nationals. The prediction includes a two-year, $14 million contract. Re-signing Kintzler, who made $2.925 million in 2017, would provide the Nationals some continuity at the back end, which they haven’t enjoyed for much of their history. But Kintzler could find more money elsewhere, especially if a club deems him worthy of closing or pitching the eighth inning. Kintzler, however, doesn’t fit the profile of a typical late-inning reliever. He doesn’t miss many bats and relies on soft contact. Perhaps that will prevent clubs from pricing the 33-year-old out of the Nationals’ range.

Perez likely won’t be back because Washington has its fair share of cheaper left-handed options and Blanton will be 37 coming off a down year. Which leaves Albers. Former manager Dusty Baker repeatedly called Albers, who posted a 1.62 ERA after signing a minor league deal last offseason, “the find of the year.” He’ll garner a major league contract this time, perhaps a multiyear deal, though he’ll be 35 next season. His prospects could depend on Kintzler; maybe the Nationals will turn to him if Kintzler moves on.

Other free agents include Juan Nicasio, Pat Neshek, Addison Reed and Bryan Shaw. The Nationals could even try to acquire a closer and have Doolittle and Maddon set up, building on a strength at a time when bullpens are more important than ever. But there isn’t much of a selection in free agency. Wade Davis and Greg Holland headline a shallow free agent closer class, and both were given qualifying offers. If they reject them, they will come attached with draft compensation, though the penalties aren’t as severe as in the previous collective bargaining agreement. A closer would probably arrive via trade.

Washington has options, internally and externally, to fill out its relief corps. And, as they proved in 2017, the answers can arrive in a variety of ways. There is no science to bullpen construction. Relievers are volatile. One year, they’ll post a 2.64 ERA and strike out 12.4 batters per nine innings, the next they will surrender home runs at a historic clip and compile a 7.27 ERA (see: Kelley, Shawn). The Nationals may unearth another “find of the year” on a minor league deal or add big-name pieces to their bullpen in July as they have done each of past three seasons. The goal is to have it all in place by next October.

More on the Nationals:

Who might the Nationals target in free agency?

Max Scherzer, Stephen Strasburg named NL Cy Young Award finalists

Bob Henley will return as Nationals’ third base coach

Kevin Long, once viewed as a managerial candidate, will be the Nats’ hitting coach

Mike Rizzo ‘optimistic’ Daniel Murphy will be ready for Opening Day