WASHINGTON — When Bryce Harper writhed in pain on the field and clutched at his left knee and then didn’t put weight on his left leg as he was helped off, the possibility of a career-altering injury seemed realistic.

Harper was definitely worried.

“Of course you’re going to think the worst,” he said. “It’s definitely a bad feeling.”

That bad feeling subsided as Harper walked up the stairs from the dugout to the clubhouse, tested his knee by jumping up and down and then got the MRI results that revealed what the Washington Nationals hope is season-saving news. General manager Mike Rizzo said Harper has a “significant” bone bruise in his left knee but avoided the kind of ligament or tendon damage that would have put a pin in the team’s World Series aspirations.

There’s no definitive timeline for Harper to return, but manager Dusty Baker referenced 10 days to two weeks. At the very least the Nationals are hopeful the star outfielder and NL MVP candidate will be back before the end of the season.

“It was definitely a relief,” Harper said Sunday. “We’re going to take some time to definitely let it heal. I want to be at 100 percent whenever I play. The World Series is definitely on my mind, playoffs, things like that.”

ROCKIES: Slugger Nolan Arenado says he feared the worst when he took an 88-mph fastball on the left hand Sunday.

X-rays were negative, and the injury was diagnosed as a bruise, which took a little sting out of the pitch.

“Whenever you get hit in the hand, it scares you,” said Arenado, the major league leader with 100 RBI. “It hurt real bad. It got real tight. That was my concern – how tight it was getting. Luckily it’s not broken, but it hurts a little bit.”

Arenado was hit by a pitch from Vance Worley. Following the Rockies’ 5-3 loss, Arenado said his hand was swollen and stiff, but he hopes to be sidelined for only a couple of days and avoid a stint on the disabled list.

The All-Star third baseman has missed only three games this season and is batting .311.

PADRES: San Diego committed to its rebuilding program under Andy Green, giving their manager a three-year extension through 2021.

“I can’t hide my happiness,” Green said. “I’m thrilled and excited to be able to staying here to lead this organization. There is no other place I’d rather be.”

Green, 40, is in the second year of his original contract with the struggling Padres (51-65), and the organization is encouraged by the way he has handled his young team.

MARLINS: NBA Hall of Famer Michael Jordan has a small stake in Derek Jeter’s investment group that reached an agreement to buy the Miami Marlins, a source said.

Jordan already owns the NBA Charlotte Hornets. He and Jeter have known each other for more than 20 years and are close friends.