A day after outfielder Bryce Harper visited James Andrews for a second opinion on his swollen left knee, the Washington Nationals said the orthopedic surgeon reaffirmed the team medical staff’s original diagnosis of patellar bursitis, adding that there is no structural damage to the knee. Harper received a platelet-rich plasma (PRP) and cortisone injection into the bursa sac, Nationals trainer Lee Kuntz said Tuesday, and could resume baseball activities in a week if the swelling subsides.

Harper will remain in Washington during the team’s nine-game road trip and will be evaluated in a week.

The Nationals are 6-13 without Harper in the starting lineup following an 8-3 loss to the Colorado Rockies on Tuesday night.

Kuntz said the cortisone is expected to help reduce the inflammation; the PRP injection, spun from Harper’s blood cells, is for any potential infection and to help protect the knee. The decision to administer the injections was made jointly by Andrews and Nationals team physician Wiemi Douoguih, who made the original diagnosis. Harper hasn’t played since he aggravated the injury May 26; the original injury occurred in a May 13 collision with the outfield fence in Los Angeles.

The large brace Harper was spotted wearing in the airport after his visit with Andrews was to immobilize and rest the knee, Kuntz said. Harper’s agent, Scott Boras, said Tuesday that the outfielder did not undergo surgery.

“These are all good things,” Kuntz said. “We want him to rest the knee, that’s why we put him in the immobilizer. We’ll reevaluate him in one week’s time and if everything’s a go, then we will resume activity with him and get him going as quickly as we can.”

The Nationals hope Harper’s knee will hold up for the duration of the season with this course of treatment. Kuntz appeared unwilling to address what would happen if Harper’s knee doesn’t respond to the injections.

“That’s a bridge you’ll cross when you come to it,” Kuntz said. “[Doctors] tell the player always risks and benefits of things and all of this was positive things for Bryce. Just rest this, we’ll see how it responds and we’ll go from there.”

It’s unclear what prompted Harper to agree to the cortisone shot. Harper rejected the treatment last week: “I don’t want to put any of that stuff in my knee or in my body. I think that can do some damage to my knee. I’m not going to do that at 20 years old.”

Harper’s father, Ron, said he and his son had discussed the possibility of a cortisone shot as one possible outcome of the visit with Andrews. Those close to Harper put no pressure on him to receive a shot, leaving the decision up to him. It appears Harper, who has been itching to return as the offense has continued to slump, may have seen the cortisone shot as a quick way to get healthy and reduce the swelling.

Tuesday’s news reflected what the Nationals believed all along about Harper’s injury. General Manager Mike Rizzo said over the weekend that he had “no worry” that the visit to Andrews, the surgeon who operated on the right knee of Washington Redskins quarterback Robert Griffin III, would reveal structural damage and that it was a matter of procedure to seek a second opinion.

Despite not playing since May 26, the swelling hadn’t subsided much and, after it increased following a light workout in the pool Thursday, the Nationals scheduled Harper’s appointment with Andrews. In recent days, however, Nationals officials said Harper’s inflammation had subsided.

On May 14, the day after his initial injury, Harper received X-rays on his left knee and left shoulder; Rizzo described Harper’s status as “day-to-day.” Harper pinch-hit on May 15 and started May 16. He bounced in and out of the lineup until May 26, when he aggravated his left knee with two headfirst slides and with a foul ball off his knee.

After an MRI exam the Nationals diagnosed Harper with bursitis, a heavy swelling of one of the knee’s bursa sac. He sat out the next five games, and the Nationals placed him on the 15-day disabled list June 1. Harper said the following day he should have landed on the disabled list after an April 30 hit against the right field wall in Atlanta which bruised his left side.

Harper’s father has said he and his son feel the Nationals have handled the outfielder’s injury appropriately. “I wish he was out there right now playing,” Manager Davey Johnson said. “Injuries, it’s a tough thing.”

Adam Kilgore contributed to this report.