Is Melancon a good long-term investment for Nationals?

As we transition into offseason mode here, we're reviewing each significant player on the Nationals roster. We continue today with Mark Melancon, who excelled after his acquisition at the trade deadline but now is a free agent.

PLAYER REVIEW: MARK MELANCON

Age on opening day 2017: 32

How acquired: Acquired from Pirates for Felipe Rivero and Taylor Hearn, July 2016

MLB service time: 6 years, 98 days

2016 salary: $9,650,000

Contract status: Free agent

2016 stats (PIT+WSH): 2-2, 1.64 ERA, 75 G, 47 SV, 4 BS, 71.1 IP, 52 H, 16 R, 13 ER, 3 HR, 12 BB, 65 SO, 1 HBP, 0.897 WHIP, 2.8 WAR

Quotable: "I just think that his resume and his performance level dictated that he was a guy to really go after and attack. Although we'll have him for a short time this year, we thought that the situation and the deal that we had to make to acquire such an accomplished reliever was worth it." - Mike Rizzo, after trading for Mark Melancon on July 30

2016 analysis: The Nationals desperately needed a reliable closer this summer, and few (if any) have been more reliable over a prolonged stretch than Mark Melancon. He may not have the name appeal of Aroldis Chapman, Craig Kimbrel or Andrew Miller, but he ranks right alongside those guys as one of the best late-inning arms in the sport.

And Melancon continued that trend during his two-plus months in D.C. In 30 appearances, he posted a 1.82 ERA, recorded 17 saves in 18 attempts and struck out 27 batters while walking only three. He was durable enough to pitch in 53 percent of the Nationals' games following his acquisition and at no point appeared to be taxed by the heavy workload.

Melancon has so much success because he's able both to consistently throw the ball over the plate and also induce weak contact. Of the 107 batters that faced him after the trade, only six recorded extra-base hits, producing an abysmal .279 slugging percentage. Combine that with their even-worse .202 on-base percentage against Melancon, and it's easy to see why the right-hander is so tough to face at the end of games.

2017 outlook: The Nationals knew they were only assured of having Melancon on their roster for the final two months of this season. Now a free agent, he'll be free to sign anywhere starting Tuesday. And the Nats won't get anything back if they lose him.

Because Melancon was acquired in-season, the Nationals are not allowed to extend him a qualifying offer, and thus can't receive any draft-pick compensation should he sign elsewhere. That could, however, be an extra motivating factor for them in trying to re-sign him.

Melancon was happy in Washington, and the Nationals were plenty happy with him. Are they willing, however, to make the kind of long-term commitment so many executives are reluctant to make to relief pitchers, whose careers are notoriously erratic and tend to peak early.

For what it's worth, Melancon might well be a rare exception to the rule. Over the last four seasons, his ERA had fluctuated between 1.39 and 2.23. He has never allowed more than one batter to reach base per inning during this stretch. His strikeout rate remains consistent and his walk rate actually has gone down.

If ever there was a reliever who seemed like a relatively safe bet to maintain his performance for several more years, this would seem to be the guy. It still remains to be seen whether the Nationals feel that way, and whether Melancon wants to remain in D.C.