For the first time in four days, Bryce Harper came out to the field Thursday evening and took batting practice with his teammates. He ran in the outfield, under the watchful eyes of the Washington Nationals’ trainers, and tested his swollen left knee. But he was still not in the lineup, and the bursitis in his knee is still an issue. The hope is he will be ready to return to the lineup by Friday, when the Nationals visit the Atlanta Braves for what figures to be another installment of a highly intriguing season series between the divisional rivals. The Nationals trailed the Braves by 4 ½ games before Thursday’s games. “He’s shooting for [Friday],” manager Davey Johnson said. But it’s difficult to know if that hope will become a reality until the Nationals’ integral outfielder arrives at Turner Field. The swelling in his knee is down, but not gone. The pain is less, but still evident. The fear he could aggravate it by sliding — whether in the outfield or on the basepaths — is present. “I’m not going to go out there and play 75 percent and one thing is going to make it blow up,” Harper said. “I just don’t want to make it worse and then be out for six weeks or something.” It’s left Harper and the Nationals in a frustrating situation. The issue is such that the Nationals’ doctors are confident there is no structural damage in Harper’s knee, and that he cannot worsen the problem or have it lead to a significant injury by playing through it. General manager Mike Rizzo said Tuesday it is “not a debilitating injury.” “It’s a nuisance injury,” he said. “The injury doesn’t get worse with wear and tear. When the swelling goes down and he’s able to play, he’s able to play.” But it’s painful, and as long as the inflammation is present, the possibility of aggravating it and keeping it inflamed longer is obvious. The fact that Harper was taking batting practice on the field, his second day of hitting after doing so in the cage Wednesday, was a good thing for the Nationals. But as Johnson walked away from the batting cage, his evaluation of Harper was that he still looked a little “gimpy.” “It’s mostly on how [he] feels,” Johnson said. “I think it’s lessened enough to where he feels a lot better about it. But until he goes out there and does a few things, he’s not going to know. He says it doesn’t bother him to hit, but we’re not going to have a designated hitter in Atlanta.” The Nationals hope the swelling will continue to reduce — and that they won’t have to do something drastic such as drain the knee, although that does not appear to be a consideration at this point. The belief remains that Harper will not require a disabled list stint.