Ryan Zimmerman has been pressing at the plate, hitting the ball to the left side of the field and hitting the ball on the ground more than he ever has in his career. (Jonathan Newton/WASHINGTON POST)

Around 3:30 p.m. Tuesday, Ryan Zimmerman emerged from the dugout with a group of teammates, Michael Morse and Danny Espinosa among them, to take early batting practice under the supervision of Manager Davey Johnson and hitting coach Rick Eckstein. It’s not something the Nationals’ $100-million third baseman does often. But this .229 batting average isn’t a normal slump.

For so long, while the Nationals were at their worst, Zimmerman was at his best: a slick-fielding third baseman who could hit for average and power. In February, they signed him to a six-year contract extension, making him one of the cornerstones of the franchise.

Since he hurt his shoulder and returned after missing 13 games in early May, he has looked little like his former self.

He appears to be pressing at the plate, hitting the ball to the left side of the field and hitting the ball on the ground more than he ever has in his career. The injury — officially diagnosed as an inflamed right shoulder joint — is not 100 percent healed, he admitted.

“My shoulder is good, good enough,” he said before Tuesday’s game. “I wouldn’t play if I didn’t think I could help the team. There’s a lot of people that play banged up here and there. I’ve been feeling better and better each day.”

The issue isn’t just that Zimmerman’s power numbers (three home runs in 205 at-bats) are down. All his numbers are down. Though 51 games is a small sample size, his .300 on-base percentage and paltry .322 slugging percentage are well below his career marks. Only twice this season has Zimmerman had consecutive multi-hit games for an offense that ranks in the bottom third of the National League in runs scored per game (3.85).

“It’s tough,” he said. “It’s been easier because we’re winning. Winning kind of makes everything a lot easier. It’s frustrating because I want to help the team and do what I can to help us win more.”

Zimmerman has also been impatient, seeing career-low pitches per at-bat. On Sunday, he needed only seven pitches to go 0 for 4. He averaged 2.93 pitches at-bat in a three-game series against the New York Yankees this weekend, well below his 3.93 career average.

Asked whether his shoulder has caused him to hit the ball on the ground at the highest rate of his career, Zimmerman said he wasn’t sure. He has grounded into a team-high 10 double plays — also at the highest rate of his eight-season career.

“If things are bothering me it changes the way you hit, changes the way you swing,” he said. “But like I said all along, I would never use that as an excuse. If I wasn’t good enough to play, I wouldn’t be out there. I don’t think that’s fair to the team.”

Zimmerman said he and Eckstein watched video of his at-bats and weren’t planning any dramatic changes. He said he would try lowering his hands a little to see how that would help – although it wouldn’t be the first time he’s tried that. “We’ll see,” he said.

Zimmerman said his contract is not weighing on him.

“I’ve already had one contract,” he said. “Obviously this one is longer and more money. But I’m so comfortable here. Obviously you want to do well whenever, making the league minimum or making $30 million a year.”

Careful about when to approach a slumping player, Johnson spoke with Zimmerman and told him to simplify everything and clear his mind.

“When you sometimes think about some things that have been bothering you a great deal, you lose sight of the fact that your main job is the opposing pitchers and timing and having good timing on all his pitches,” Johnson said. “I thought that’s where the injury was causing the problem to do that.”

On Tuesday, Zimmerman spent extra time hitting, first working in a group with Morse, Espinosa and Rick Ankiel, then more swings with the next group of hitters. And then, during normal batting practice before the game, Zimmerman was back on the field taking more swings.

“Baseball is one of those funny sports and you’ll get like a swinging bunt or something and go like 25 for your next 50,” he said. “One of those streaks would be nice.”