(Toni L. Sandys/The Washington Post)

Nationals Manager Davey Johnson spotted Bryce Harper in the clubhouse around 2 p.m. on Monday, the day Harper was reinstated from the disabled list after missing 31 games with left knee bursitis, and the two shook hands. Johnson was, jokingly, in disbelief. “Is that really you?” Johnson said he asked Harper. “You okay? You ready to go?”

The answer, of course, was yes. Hitting coach Rick Eckstein already had the day’s lineup written out with Harper’s name in it — which also included an old spot for Jayson Werth and new one for Anthony Rendon — before Johnson arrived at the stadium. Harper was so eager to return he joked on Twitter the night before that he would sleep in his uniform.

“I’m excited to get going,” Harper said. “I’m excited to be back out there on the field and back on this club and really looking forward to (Monday night) and just getting going again.”

The Nationals, however, are the ones most excited to get Harper back.  The Nationals went 15-16 without him. When he starts, they have gone 25-18 – a 94-win pace. Since he last played on May 26, the Nationals offense has posted a collective .245/.294/.409 and 3.93 runs per game.

“I think not only his bat but I think the energy that he brings,” Johnson said. “He takes a lot of the focus and he’s a competitor. Just having that 20-year-old energy running around 100 percent. I’m sure he’s still going to run into a wall. I’m sure he’s going to dive head-first. He did that two times on his first day back. But I don’t want to put a damper on that. That’s who he is and that’s how he plays the game. That’s great.”

Even though he was gone for over a month, Harper said it didn’t feel that long. (Johnson, however, felt differently, perhaps because he has dealt with the frustrations of an offense without Harper first-hand: “I seems like I haven’t seen him in half a year. It seems that long.”) Harper said he was more concerned about the condition of his knee. He wanted to make sure it could hold up to his all-out style of play and all the sliding and banging that accompanies it before he could return.

The swelling in his knee is minimal and nothing to be concerned about, he said. He will wear a knee pad on his left knee all season. He tested his knee as hard as possible sliding and diving in his four rehab games and the left knee responded well. In his first rehab game at Class A Potomac, he slid into second on a bloop double to left and knew instantly that his recovered knee could withstand the rigors.

“It was more of just thinking about myself and trying to get back out there when I felt I could,” he said. “I didn’t want this to linger all season and have to sit and miss games. I’d rather get it out full force and be able to play the rest of the season than keep going and having to sit a game, sit a game.”

Like Johnson, Harper is pleased that the Nationals are nearly whole again. Wilson Ramos could return as soon as this week. Harper wants to do his part to help boost an inconsistent offense.

“Sometimes things go your way and sometimes they don’t,” he said. “We’ve got the whole second half to get going with our team and really pound it out. We got all those hits yesterday and scored all those runs yesterday, it’s hopefully on the brighter side for us.”

Johnson placed Harper back at the spot where he hit before he got hurt, placing him in third in the lineup in between Jayson Werth and Ryan Zimmerman. The move pushed Rendon, one of the Nationals’ best hitters since his second call-up a month ago, down to the seventh spot of the lineup. Werth is hitting .272/.333/.440 but Rendon posted a slash line of .310/.360/.431.

Johnson explained that he wanted to return to the original lineup of the beginning of the season. He liked the left-right balance, the veteran hitters surrounding Harper, Werth’s ability to get on base, his dynamic with Harper and the power of Werth, who has eight home runs in 184 at-bats. Also, he said, he has had little chances to evaluate that lineup construction because of injuries.

“Rendon did a heck of a job,” Johnson said. “His on-base percentage, his batting average, his approach was great. The problem is Werth has a little more pop. He has a history of being able to get on the base. That’s his M.O., get on base, take some pitches. But mainly, when you have three left-handers in the first five, the guys that I have separating them, I want them to give the manager on the other side pause before he brings his bullpen, a left-hander to go through those three left-handers.”

“It’s all about matchups late in the ball game that you want to create. And he is more of a threat at this point than Rendon is. It’s pretty easy. Rendon did the job that I want in the two-hole getting on base. …. It’s not a slap at Rendon at all. The other guy has a proven track record. One of the reasons we were so successful last year is because I led him off and Harper behind him. So they’re used to having that relationship so I pretty much thought I would go back there.”