With slugger Michael Morse back, the Nationals are getting closer to the lineup they envisioned on opening day. (Julio Cortez/Associated Press)

All season, the Washington Nationals have wondered what kind of team they would be if they had a decent offense to complement their top-ranked pitching staff. For 50 games, they improvised and sputtered, going 29-21 for a slim lead in the National League East despite sending up baseball’s sixth-worst offense. The Nats had good excuses for a bad offense. But they are out of them now.

On Friday, a lineup hung on the clubhouse wall that, for the first time this season, had Michael Morse, the team’s one true slugger last season, batting cleanup after missing almost three months because of a muscle tear in his side.

“Better late to the party than never. June 1 is my opening day,” said Morse, wearing shoes — with “Opening” on the back of one heel and “Day” on the back of the other. Morse had the spikes made for the Nats’ first game April 5, but he’s glad to wear them now. And he won’t mind waiting a day after Friday’s game, which should’ve been called earlier amid torrential rains and tornado warnings, was postponed 20 minutes before game time.

“There is so much more potential here. We haven’t hit our stride yet,” Morse said. “It’s really going to be fun.”

The 6-foot-5, 245-pound Morse has been the Nats’ missing link. Some think his .303 batting average and 31 homers last season were flukes. That ignores all evidence. In his last 716 at-bats in Class AAA, he hit .317. The last two years in D.C., another 788 at-bats, he has hit .298 with a star’s .896 OPS (on-base plus slugging percentage). He’s streaky, but when the final numbers are counted, he produces.

For weeks, the most annoyed and frustrated man in a Nats uniform has been Manager Davey Johnson, who said, “Morse has been telling us for the last month that he felt great.”

When did baseball change so that players had to be “100 percent” recovered from any and all types of injuries before the entire organization would sign off on letting their prized assets play?

“That’s a good question,” Johnson said. Long ago, “if you pulled a hamstring, you shot up and played. I’m not saying that was wise. But we might have gone a little overboard on ‘100 percent.’

“I’m not a real fan of the MRI. Maybe it’s the culprit,” Johnson added, half-kidding. “We study everything. Why don’t we do some studies of MRIs on healthy guys to give us a baseline.”

In Davey’s view, if you took an MRI exam of a burger and fries, the meal would be put on the 60-day disabled list.

“To me, the question has always been, ‘If he plays, can it get worse?’” Johnson said. “If the answer was ‘No,” then it was a question of pain tolerance. Now, it’s ‘no,’ but we want to let the inflammation go down.”

When it comes to injuries such as catcher Jesus Flores’s current pulled hamstring, which can get re-injured more severely, Johnson is an ultra-cautious manager.

The frustration is over for Morse, who says, “Throw me in now.”

The Nats will still be without outfielder Jayson Werth for two more months and catcher Wilson Ramos for the rest of the season. But that damage shouldn’t be overestimated. The whole sport is riddled with injuries. And rookie Bryce Harper has, so far, actually exceeded Werth’s production in right field. Harper’s .861 OPS (for a full season) would be the second-highest in history for a teenager, behind only Mel Ott. The loss of Ramos hurts; he has more power than replacement Flores, but the gap in their value isn’t large.

Besides, the Nats have found unexpected ammo in switch-hitting rookie Steve Lombardozzi, batting .365 left-handed (but .111 right-handed), who has won a spot batting leadoff against right-handers.

The keys to an offensive revival are all in place, especially the three engines that have been almost silent this season: Morse; Ryan Zimmerman, who has just 14 homers in 534 at-bats since the beginning of last season; and Danny Espinosa, who endured a slump from last July until three weeks ago when he started showing signs of life after working with Johnson.

Zimmerman’s lost power, after a trip to the disabled list because of shoulder-joint inflammation, has been a $100 million question this spring with two homers in 142 at-bats.

“Zim rehabbed in the three hole in the NL East. That has a lot to do with it,” General Manager Mike Rizzo said. “Someone is going to pay pretty soon. He’s going to get his numbers.”

The streaky Zimmerman never knows when he’ll break out with a 25-for-50 tear that transforms his season, or a 30-game hitting streak. But he says, “Batting practice the last few days has been a lot better. I’m still a little late, not really on time. But I’ve started to feel like I can drive the ball.”

For Espinosa, his agony of strikeouts goes back to last July. Fans have ridden him hard. But Johnson has stuck with him, calling him “pound for pound, as powerful as any hitter in the league.”

“Somewhere, I picked up one bad habit: too much body and not enough hands; I developed a loop in my [left-handed] swing,” said Espinosa who is still excellent right-handed. “Davey and I have worked on it — shorter, quicker, hit more down on the ball. It’s been working better.”

For his last 22 games, he has put up even better numbers than the first half of last season. Will it last?

“I like the way things are looking right now,” Rizzo said. “Morse back, Espinosa is making strides. Flo is doing a good job back there. [Reliever Brad] Lidge is in the near future. We’ll finally have a team that resembles the club we thought we’d have on opening day.”

Washington’s pitching has been lighting up the sky all season. For the Nats’ offense, with Morse back and Harper mashing, it’s time for the rest of the lineup to produce more now that it’s finally being asked for less.

On bad baseball teams, nothing matters much, except to the club itself. But when you’re in first place, every development suddenly carries weight.

Two years ago, if the Nats got their cleanup hitter back from the disabled list, few would’ve noted it. Now the whole NL East has an eye on Morse.

“When I first got hurt, I thought, ‘A day or two.’ If somebody had told me I’d miss three months, I would have laughed in their face,” Morse said.

“Throw me in there. I hope I’m that rabbit’s foot.”

For Thomas Boswell’s previous columns go to washingtonpost.com/boswell.