Nationals right fielder Bryce Harper reacts after suffering an injury against the San Francisco Giants on Saturday night. (Michael Owens/USA Today Sports)

Bryce Harper feared the worst as he wriggled in agony on the infield dirt behind first base at Nationals Park late Saturday night. He had just slipped across a slick first base, his left leg planting and buckling before he went airborne and landed on his right side. He was grabbing his left knee in shock. He thought to himself, “It’s 10 o’clock at night and we’re playing a game in the rain.” He thought about teammate Adam Eaton’s season-ending knee injury on an eerily similar freakish play a few months earlier. It was impossible not to assume he was destined for a similar fate.

“Of course you’re going to think the worst, and I’m one of the worst at it,” Harper said. “I think I’m going to die every time I have a stomachache.”

Nationals General Manager Mike Rizzo initially felt dread for his 24-year-old MVP candidate when he watched the clip “ad nauseam.” He worried the Nationals, already subjected to a remarkable series of injuries this season, had received the biggest blow in the first inning of a game against a last-place club with no impact on the postseason picture.

But their initial fears were allayed when Harper insisted on walking on his own into the clubhouse, where he tested the knee with some jumps and “figure skater stuff.” It was sore, but nothing he hadn’t felt before. An MRI exam later confirmed his optimism. It showed no structural damage in the knee. He does have a significant bone bruise on the inner portion of the knee resulting from a hyperextension, but the team is optimistic Harper will return before the end of the season.

“Although we feel we’ve dodged a bullet a bit here with any long-term ligament and tendon damage, the bone bruise is something of significance,” Rizzo said on Sunday morning. “And we’re going to treat him cautiously and hopefully have him back later on this season.”

Harper was walking with a slight limp without crutches or a knee brace between the Nationals’ two games Sunday. He was officially placed on the disabled list earlier in the morning with “a hyperextended left knee.” Doctors said Harper’s youth, athleticism and flexibility helped him avoid season-ending — and franchise-altering – ligament and tendon damage. Harper attributed it to his double-jointedness, which he credited his mother for passing down.

Recovery from a hyperextended knee varies by severity. A mild to moderate hyperextension, for example, could take a couple of weeks to a month. Harper and the team didn’t have a timetable on his return, but Harper said he would play through the injury if it were the postseason. He also hinted he would like to return in time to give himself a chance to win his second National League MVP award in three seasons.

“If I feel good, I’m going to play,” Harper said. “If I don’t feel good, I’m not going to go out there and play. I want to be at 100 percent as I go out there. I played through injury before and I’m not going to do that anymore in my career. Of course, if we were in the playoffs right now, I’d tape it up and go out there and hobble the best I could and do that.”

The Nationals can afford extreme caution because they entered Sunday owners of a 14 1/2-game lead in the National League East. That cushion, along with San Francisco’s miserable campaign, made Saturday’s game essentially meaningless in the standings. The Giants were 19 1/2 games out of the second wild-card spot entering Sunday. They aren’t making the playoffs. The Nationals almost definitely are.

With that as the backdrop, Major League Baseball controlled whether the clubs played on Saturday night, because the Giants aren’t returning to Washington this season. The league delayed the start of the game in anticipation of severe thunderstorms, which soon arrived. It then decided to start the game at 10:05 p.m., a start time that was announced at 9:22 p.m. Rain, however, continued falling and was still falling when Harper slipped on first base hustling down the line to beat out a groundball.

“It’s part of the game, part of baseball,” said Harper, who began his news conference expressing his disdain for wet bases and added it felt like he slipped in the shower. “Too bad we don’t have a roof. That’s about it. It was definitely sunny at 1 o’clock yesterday, but nobody understands the weather. It’s the best job in the world, weatherman. You can be wrong and still have your job.”

Michael A. Taylor, who was on a rehabilitation assignment with Class AA Harrisburg, was activated in Harper’s place Sunday. The Nationals also recalled Pedro Severino as the club’s 26th man for their split doubleheader against the Giants.

The moves leave the Nationals still with 11 players on the disabled list, but breathing a huge sigh of relief. In addition to Taylor, shortstop Trea Turner and outfielder Jayson Werth are expected to return in the coming weeks. The Nationals expected to be whole again for when games matter before Harper’s injury. They could seemingly still be whole — or close to it, with Eaton out for the season — for the playoffs despite Saturday’s scare.

“I think in this scenario we all have to think positive, that these guys will be back like the cavalry right on time,” Nationals Manager Dusty Baker said. “From watching all the war movies and cowboy movies, I believe in the cavalry.”

There is, however, no guarantee Harper will return or that he will return at 100 percent and clicking for a playoff run. He has seven weeks and five days. Game 1 of the National League Division Series is scheduled for Oct. 6.

“You just try to hope for the best and pray for the best,” Harper said. “And I think we got the best possible news that we could.”

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