Jeremy Guthrie (80) leads a group of pitchers running sprints early in spring training. If he makes the team, his role would be anything but a sprint; he’d be “long man” out of the bullpen. (Jonathan Newton/The Washington Post)

WEST PALM BEACH, Fla. — Conventional baseball wisdom, under fire more these days than ever, concludes that each well-constructed bullpen must include a designated “long man.”

That pitcher’s inglorious duties amount to being the ever-ready backup plan, the worst-case scenario guy picked to preserve the strength of less-disposable relievers.

Sure, a manager could call on that long man in a close game, for an inning here or there, but then that pitcher would not be available in case of blowout-related trouble. Long men, perhaps more than anyone, are pigeonholed by their multi-inning versatility. If all goes well, they are not used much at all.

The Washington Nationals, generally traditionalist in their baseball dealings, must decide how much they value a long man as they lock down their Opening Day bullpen during the next two weeks. As things stand, reserving a roster spot for a pitcher like that might force the Nationals to lose a more valuable late-inning type.

Do the math: Oliver Perez, Joe Blanton and Shawn Kelley all have major league deals. Barring injury, they are locks. Blake Treinen and Sammy Solis have options remaining, but emerged as relied-upon staples last season. They, too, seem certain to make the team.

While some teams have considered carrying 13 pitchers, meaning an eight-man bullpen and a four-man bench, Nationals General Manager Mike Rizzo said Monday that he expects to break camp with 12 pitchers — five starters and seven relievers.

Nationals relief pitcher Enny Romero. (Jonathan Newton/The Washington Post)

That leaves two spots unaccounted for, with two front-runners to occupy them: young Koda Glover, who has more strikeouts this spring than anyone on the Nationals staff, starters included, and hard-throwing left-hander Enny Romero, who the Nationals acquired from the Tampa Bay Rays this offseason — and had their eye on since the 2014 trade that sent them Felipe Rivero instead.

With Perez and Solis already filling the traditional lefty quota, the easiest solution would be to let still-unfamiliar Romero get some innings in Syracuse, leaving room for a long man. But Romero, 26, is out of options, meaning he would have to clear waivers before heading to the minors. A left-hander with a fastball that hit 100 mph in the World Baseball Classic seems unlikely to clear waivers, so the Nationals would probably lose him.

Glover has options, but losing him means leaving the promising young closing prospect in the minors. Keeping both Glover and Romero would probably give the Nationals the best seven relievers possible, but it would also require them to sacrifice the long man.

“I’ve thought about a lot of stuff. We haven’t talked about it yet. You need that guy,” Nationals Manager Dusty Baker said. “Unless you just have a five-man rotation that’s unbelievable, but those are hard to find.”

The Nationals’ rotation, which threw the third-most innings in the National League and maintained the second-best ERA, returns intact this season.

I think it really depends on the starters. Last year, we didn’t necessarily need one,” Shawn Kelley, potential closer, said. “ … I don’t think you need one if you have those utility guys who can throw two or three innings, the hybrid reliever.”

Treinen and Blanton threw three innings each in a minor league game Sunday, part of the Nationals’ effort to stretch them out before the regular season begins. Treinen, who trained as a starter every offseason but this one, said he feels comfortable going multiple innings. Solis, who went more than an inning in 11 of his 37 appearances last season, said he feels comfortable going two innings one day and another the next — or even two innings on back-to-back days, though “that might be a little aggressive.”

Blanton pitched more than an inning for the Dodgers four times in the playoffs alone, though Dave Roberts used him more as a single-inning reliever for most of the season. Kelley is two Tommy Johns in and therefore less helpful in an inning-eating effort. Seemingly rubber-armed Oliver Perez went two innings in one outing last year — but then threw a total of three innings in September, as Baker settled more on using him in matchups than full-inning duty.

“We’ve got guys who can pitch multiple innings,” Rizzo said. “So yes, I would feel comfortable going into the season without a true long man.”

Pitcher A.J. Cole, right, hands the ball to Nationals manager Dusty Baker as he is taken out of the game in the second inning of a Spring Training game in February. (Toni L. Sandys/The Washington Post)

If the Nationals were to take a long man, they would likely choose between A.J. Cole, Vance Worley and Jeremy Guthrie. Worley and Guthrie have both been full-time starters for multiple major league seasons, and both of them started games for the Nationals this spring — Guthrie weeks ago, Worley on Monday. Worley allowed three runs in 3 1/3 innings Monday. Guthrie is pitching to a 3.48 ERA, with a fastball that hit 94 and good command of his secondary stuff.

Last year, the Nationals carried Yusmeiro Petit for that role, though they hardly used him down the stretch. While he was available to make a spot start when Stephen Strasburg was a late scratch one night in Los Angeles, the Nationals generally adjusted their roster and called up Cole, Lucas Giolito, or Reynaldo Lopez when they needed a starter, rather than relying on Petit.

“Our goal is to have option-able players,” said Rizzo, who has Cole, Austin Voth and perhaps even Erick Fedde as options should he need to shuttle pitchers in and out this season.

Perhaps the Nationals will decide to buck baseball tradition and start the season without a designated long man on their roster — and risk exhausting their bullpen should a start or two go awry.

“If you’re on a successful team that’s getting good starts like we were last year, you’re kind of wasting a spot,” Kelley said. “But it’s just like anything else in baseball. You’re damned if you do, damned if you don’t.”

More baseball:

Livan Hernandez emerges as a valued voice during spring training

Boswell: Roark, finally, gets start he deserves in World Baseball Classic

Kelley hasn’t been seen much this spring. Looks can be deceiving.

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