(J Pat Carter/AP)

The Washington Nationals have missed their best player for more than two months. They’ve missed the buzz in the crowd when Ryan Zimmerman charges a slow-rolling groundball and whips a sidearm throw across the infield, the steadiness he provides in their clubhouse, the fear from the opposing dugout that he might walk to the plate in the ninth inning with the game in the balance.

They are on the brink of having all of that for the first time in 58 games, but there is also something simpler that they have been missing. “It’s just having Zim,” Nationals shortstop Ian Desmond said. “It’s like missing your brother for the whole season.”

The Nationals will activate Zimmerman off the 15-day disabled list Tuesday after he missed 58 games, all but eight games of the season thus far. The Nationals kept afloat without Zimmerman, going 27-31, but they know what he means.

“A game-changer,” infielder Alex Cora said. Starting pitcher Jordan Zimmermann admitted he’s been following Zimmerman’s minor league rehab box scores. Right fielder Jayson Werth called Zimmerman’s return “a shot in the arm.” Manager Jim Riggleman has likened Zimmerman’s to acquiring a star player in a trade.

Zimmerman last played April 9, when he slid into second base and felt a sharp pain in his stomach. He underwent surgery May 3 to repair a torn abdominal muscle. For the past week, he skipped around three minor league outposts. Finally, he is back where he wants to be, and the Nationals feel whole again.

“It’s going to be huge for us,” Desmond said. “That’s our three-hole hitter. That’s the face of the franchise. That’s pretty much the Washington Nationals. He’s that guy. He can answer a lot of our questions. Just his presence alone, I think, will kind of build everybody back up. It gives us kind of that second wind to know that help’s on the way.”

The impact of Zimmerman’s absence on the Nationals’ collective psyche is difficult to measure. But the effect on the field can at least be approximated.

Last season, per FanGraphs.com, Zimmerman accounted for 7.2 wins above replacement. If Zimmerman had kept that performance consistent this season — and he was on a better pace through eight games, even if that is a small sampling — his performance would have been worth 2.6 wins over 58 games.

Without Zimmerman, Nationals third basemen this year have posted -0.1 wins above replacement. Judging by FanGraphs’ formula, then, Zimmerman’s absence cost the Nationals nearly three actual wins over the 58 games he has missed. The Nationals, currently 30-36, would probably be hovering around .500 had Zimmerman not been injured.

Nationals players also believe that Zimmerman’s bat, when slotted into the middle of their lineup, can affect other hitters. “Zim, what he does, he definitely takes the pressure off other hitters,” said Jerry Hairston, Zimmerman’s primary replacement at third base. “You’d be surprised — having that one guy can make that difference.”

Riggleman is considering how to fit Zimmerman into a lineup he recently shook up by batting Werth leadoff and the starting pitcher eighth. Wherever Zimmerman hits, the Nationals expect that the batter in front of him will see more strikes to hit and the batter behind him will have more opportunities with men on base.

“I know that he doesn’t have any problem driving runs in,” Desmond said. “He’s a fearless hitter. He’s up there ready to do it.”

Coming off a 6-5 West Coast trip, the Nationals are activating Zimmerman at a time when they could make a run. Along with the boost provided by Zimmerman’s return, the Nationals also face a favorable schedule. They have already played 40 road games — more than any team in the majors — compared with 26 home games. So, they will play 55 of their final 96 games at Nationals Park, where they are 55-52 since the beginning of 2010.

In the long view, Zimmerman’s injury may have complicated potential negotiations for a contract extension. The shortage of games will add another factor in weighing his value. Zimmerman also missed more than 50 games with a shoulder injury in 2008, and, although he spent no time on the disabled list, he missed about 20 games last season with hamstring and oblique ailments.

Then again, injuries happen, and players as great as Zimmerman do not come along often. Colorado Rockies shortstop Troy Tulowitzki had missed 112 games because of injury since 2008, and before this season he signed a contract extension for seven additional seasons worth $134 million.

A recent development added another layer to Zimmerman’s future in Washington. The Nationals selected Rice third baseman Anthony Rendon with the sixth overall pick in the draft. General Manager Mike Rizzo vowed Rendon would start his career at third base and raved about Rendon’s “Gold Glove-caliber defense” there. The underlying, tacit implication: If Zimmerman leaves in free agency after 2013, the Nationals now have his potential replacement.

That, though, is a concern for later. Tuesday night, the Nationals will take the field with the comfort that Zimmerman will be with them, the face of the franchise back on the team.