JUPITER, Fla. — Since the day the Nationals fell in Game 5 of the National League Division Series, one question has hovered like a stubborn fog over an otherwise clear roster: Who will be their closer in 2017?

Over and over people asked, as big-name closers signed elsewhere, as spring training weeks went by without an answer. Who will be the Nationals’ closer? As of five days before Opening Day, no one with the Nationals will say.

“We’ll let you know,” Dusty Baker said on Wednesday. The fog remains.

But that fog obscures a little-discussed component of the Nationals’ bullpen: its depth. On paper, where potential is most easily realized, this year’s corps could be the Nationals’ deepest Opening Day bullpen in recent memory. Yes, even without a proven closer.

Unfortunately, projecting the depth of the Nationals bullpen requires projecting that closer’s role, then counting backward from the ninth.

As of Wednesday, it seems that Blake Treinen might have the fewest knocks against his candidacy to close. (On Thursday, Baker confirmed that Treinen would close.) Baker mentions “resiliency” as a key characteristic of his ninth-inning man, and Shawn Kelley has the least “resiliency” of the three closing candidates because of his two Tommy John procedures. Baker also acknowledged a need to manage Koda Glover’s workload and the torn labrum in his hip, an injury Glover chose not to have surgically repaired but will need to treat regularly for the foreseeable future. Both Kelley and Glover, then, have knocks against the durability Baker cites as crucial.

All of that does not mean either Kelley or Glover means will not be the closer. But it does serve as an argument for Treinen and his 98 mile per hour sinker, Britton-esque in nature. For the sake of discussion here, pencil Treinen in for the ninth.

If Treinen pitches the ninth, Kelley can pitch the eighth. Kelley had the 10th-highest strikeouts-per-nine innings of any qualified reliever last season, and of all the innings he has pitched in his career, he has the most experience and lowest ERA in the eighth. Hitters are hitting .214 against Kelley in eighth-inning situations.

If Kelley pitches the eighth, Joe Blanton can pitch the seventh. Blanton held batters to the 10th-lowest batting average against of all qualified righty relievers last year, and actually had better numbers against lefties (. 186 BAA) than righties (. 192). In other words, Blanton is well-equipped to a full-inning of duty.

So too, it seems, is Glover, should he make the bullpen. Baker said earlier this week he “would love” Glover to be in the bullpen, closer or not — and indeed, the Nationals see him as a future closer at some point or another. But if he doesn’t close, Glover could serve as the third of three strong right-handed setup types, and fit in a role that would demand less of him physically and mentally at age 23. Glover threw to a 5.09 ERA in 19 appearances last season, though the extent to which his hip trouble affected him is still unclear.

While a three-headed setup monster of Glover, Blanton and Kelley is tantalizing enough, the Nationals will also have plenty of left-handed help to navigate the later innings. Internally, the Nationals see Sammy Solis as a left-handed stalwart, one of those pitchers who is a near sure thing when healthy — though staying healthy is his biggest problem. In 55 career appearances, Solis has a 2.74 ERA and more than a strikeout per inning. As a former starter, he is still built to handle multiple innings at a time.

While Baker used Solis in matchup situations last year, he is also comfortable leaving him in for full innings at a time. Oliver Perez, the sometimes-flighty veteran, will probably serve as the Nationals’ matchup lefty. Enny Romero can fit that mold, too.

The Nationals acquired Romero from the Rays, who had soured on him, hoping to revitalize the 26-year-old. If Romero threw strikes, the Nats would strike gold. If not, they would have pyrite. So far this spring, with the exception of his most recent outing, Romero showed the improved command the Nationals hoped to see. He walked two batters in 7 2/3 innings, and impressed with command of his breaking ball — a pitch he did not use to great effect during his time with the Rays. Romero is out of options, but he is also throwing a fastball in the high 90s. Lefties who do that do not clear waivers, and the Nationals seem unlikely to take the chance that he would.

Should the Nationals decide to carry a long man, the makeup of the bullpen could change. Jeremy Guthrie, the only nonroster invitee still in major league camp, looks like the man to fill that job. Perhaps the Nationals will carry eight pitchers. Perhaps they will carry seven, sacrificing a long man or perhaps even Glover to make room. As of Wednesday, the specifics are not clear. Also unclear is how closely potential and performance will align. Can Kelley stay healthy for another year? Will Blanton be as good this year as last? Can Romero maintain that command?

But what will become clear, as soon as the Nationals name a closer and settle on roles, is that this year’s relief corps contains more pitchers with late-inning potential than perhaps any the Nationals have had to date.

Treinen, Romero and Glover all average more than 95 with their fastballs. Solis, Kelley and Perez all averaged more than a strikeout per inning in 2016. The Nationals’ bullpen finished with the second-best ERA in the majors last season, during which struggling Jonathan Papelbon was their closer for four of six regular-season months. Even without someone set for the ninth, this year’s bullpen might be even deeper.

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