WASHINGTON — Bryce Harper was out of the Washington Nationals’ starting lineup Thursday night because he felt sore after returning this week from a knee injury that sidelined him for about a quarter of the season.

Nationals manager Dusty Baker wanted to make one thing perfectly clear: “Don’t,” he said, “be alarmed.”

Concern about right fielder Harper’s health is understandable, considering the 2015 National League Most Valuable Player might be the key to Washington’s postseason success.

Baker said before the NL East champions faced the Pittsburgh Pirates on Thursday that nothing new cropped up with Harper, who hyperextended his left knee during a game in August and missed 42 games.

“We decided it would be best to give him the day off,” Baker said, “and then he’ll try to play through the weekend.”

Baker expects Harper to play against the Pirates in the final three games of the regular season.

Harper came off the disabled list on Tuesday and played that day and Wednesday against the Philadelphia Phillies, going 1 for 6 with a walk.

“I’ve felt pretty good. Body feels good,” Harper said. “A little sore today (after) playing two in a row.”

Harper is batting .324 with a .418 on-base percentage in 408 at-bats this year. Despite missing so much time, he ranks second on the Nationals with 29 homers and fourth with 87 RBIs.

“Just trying to get in there and be healthy,” Harper said. “I feel good right now. And if I can just keep going and do the things I need to do to get ready for the postseason, we’ll get there.”

Washington hosts Game 1 of its NL Division Series against the Chicago Cubs on Oct. 6.

“Each day that goes by is another day that he can get sharp and well,” Baker said. “I already think he’s well, but he’s got to get sharp. I don’t see any limps. I don’t see him stumble when he turns and pivots to make a throw. He looked really good.”