WASHINGTON, DC - JANUARY, 7: Daniel Murphy is introduced by GM Mike Rizzo during a press conference on January 7, 2016 in Washington, DC. (Jonathan Newton / The Washington Post) (Jonathan Newton/The Washington Post)

On Christmas Eve, Mike Rizzo lay on his back on the rug on the floor of his Washington apartment. He had been lying there most of the time since having back surgery two days earlier to relieve pain from a lumbar compression that hurt so badly he called it “a 9½” on a pain scale of 10. Rizzo didn’t sit. He didn’t lie on a bed, just on the floor, the hardest surface he could find to minimize the discomfort.

If you want to call that image a symbol of the 2015 Nationals — flat on their backs — feel free. But if you want to view it as down-but-not-out, that’s true, too.

In that supine position, the Nats GM couldn’t do much. Except answer a phone with one hand, hold a pen to write on a pad of paper on the floor with the other and negotiate a $37.5-million three-year deal to sign free agent Daniel Murphy.

With the Murphy move, Rizzo believes he completed the last essential part of the Nats’ offseason. Maybe it didn’t constitute a jolly defiant “Die Hard” moment like “Now I have a machine gun. Ho-Ho-Ho” But it did show the Nats still could mount a fight, even after being turned down in their earnest pursuits of Ben Zobrist, Darren O’Day, Brandon Phillips and, less intensely, Jason Heyward.

“We were looking for the best left-handed value we could get, and this guy really plays the game the way I like: gritty, hard-nosed, but with a smart baseball mind,” Rizzo said at Murphy’s introductory news conference Wednesday. “He can steal you a base. Situational hits. And the brighter the lights, the more he steps up.”

Exhibit A: Murphy’s seven amazin’ postseason homers, including six in consecutive games, all of them blasted off famous pitchers. No one carried the Mets to the Series more than Murphy. Counting postseason, and why wouldn’t you, Murphy had 21 homers, 40 doubles, 84 RBI and a .282 average in 144 games.

“We like the lineup the way it is, like the roster construction,” Rizzo said, “and we really look forward to moving on to spring training.”

Partly, this is January happy talk. Murphy was the Nats’ third choice for second base after Zobrist and Phillips. But for a “show” ticket, he’s a very good payoff. The past six years, he has hit an utterly dependable .287 while being one of the most difficult hitters in MLB to strike out. Whether he hits No. 2, 5 or 6, he’ll make the Nats’ offense less all-or-nothing and, probably, tougher against top pitchers — such as the ones in the Mets’ rotation. Maybe, at 30, using his lower body more in his swing, he has developed 20-homer power.

But — there’s always a “but” — as the World Series showed, Murph sometimes plays second base with a meat cleaver. Oh, he’s a grinder who’s always trying. But next year he’ll make several of the most gruesome infield plays you’ve ever seen.

“With every player, you take the whole package,” said Rizzo.

The Nats have a history of making surprise moves late in the off-season, such as signing Max Scherzer last January for $210 million. And they may this time, too. They have the payroll flexibility and trade pieces to act dramatically. Lefty Wei-yin Chen, a Scott Boras client, is still on the open market. So is slugger Justin Upton, who grew up friends with Zimmerman in Virginia Beach. Every time you sign any free agent — cash-for-talent — you open up additional trade variations.

But the real importance of the Murphy signing is that the Nats no longer think that they must act boldly. Oh, they’d probably like to sign outfielder Gerardo Parra. But their end-of-season anxiety attack is over. They added four relief arms. They got their lefty bat at second in Murphy. They can live with what they’ve got.

Regardless of who likes it or not, the 2016 Nats may be a virtually completed project right now — including Jonathan Papelbon and Drew Storen both back in a rebuilt bullpen and a double-play combination of Murphy and Danny Espinosa at shortstop with Trea Turner maturing in the minors. The recent addition of vet utility infielder Stephen Drew, who hit 17 homers (and batted .201) with the Yankees last year is another sign the Nats feel like “we’ll play these” and still contend in the N.L. East against the Mets, who probably will lose free agent Yoenis Cespedes, too.

At a getting-to-know-you meal with the Lerners, Murphy was asked which Nats he already knew. He mentioned his wife’s close friendship with Ryan Zimmerman’s wife Heather.

“They’re helping us get settled in Washington,” Murphy said. “And I’ve talked to Pap.”

Pap? You mean the guy has a friendly nickname? Pregnant pause. Murphy gave Papelbon high marks as a pitcher and otherwise. According to one person present, Rizzo spread his arms, looked to the heavens and said, “Thank you!”

Plenty of fans might not feel that way, but a stat maven recently researched that, in the past eight years, Papelbon has the highest save percentage in one-run games (90 percent) of anyone in baseball, including Mariano Rivera.

“Papelbon was perfect all season in Philly [17-for-17 in saves] and was like that the first [14] games for us, too,” Rizzo said.

In fact, after a 2.04 ERA with the Phillies in 2014, he still had a 23-for-23 save record and a 1.65 ERA with a 3-1 record as late as Sept. 7. After that, nine runs allowed in his last eight games.

What has become clear this winter is that the Nats have had to cope with the aftermath of a black-eye season. Players, who have a choice of destinations, don’t need to see actual fire to wonder why a team has a cloud of smoke hanging over it.

Phillips wouldn’t okay a trade to D.C. O’Day, who might have been a closer option, stayed in Baltimore when everyone knew he decision was between the Orioles and Nats.

Gradually, as closer options such as Aroldis Chapman (traded) disappeared, it became clear that a tarnished Papelbon, traded at less than baseball value, would not bring a quality closer in return. And wouldn’t set the stage for a trade for a closer either. Storen for the eighth? Fine. For the ninth? Been there. So the Nats were, and still are, stuck with “Pap.” Which could be good, though touchy.

What the Nats needed was someone who truly wanted to play for them, and perhaps, stick it to the Mets, who never gave him favorite-son treatment, never tried hard to re-sign him, no matter how many positions he played or how uncomplainingly he batted in every spot in the order. Someone such as Murphy.

“Washington was such a good fit,” said Murphy, intoxicated by his first shot at postseason play and convinced the Nats would be going back there soon. “That made the negotiation short, sweet and awesome.”

Why, you could do it lying down.

For more by Thomas Boswell, visit washingtonpost.com/boswell.