Although last week’s spur-of-the-moment Twitter campaign to elect Nationals outfielder Bryce Harper to the final spot on the National League’s All-Star Game roster fell short, the 19-year-old rookie found out over the weekend that he’ll be going to the Midsummer Classic in Kansas City, Mo., after all.

On Saturday, National League manager Tony LaRussa plucked Harper to replace Miami Marlins outfielder Giancarlo Stanton, who pulled out of the All-Star Game (and Home Run Derby) to undergo knee surgery.

With the last-minute selection, Harper, 19, became the youngest position player ever chosen for the All-Star Game. Speaking to the Post, Harper was excited and maybe a bit lost for words about being picked to join baseball’s elite players only four months into his big-league career.

“I don’t have words to explain it right now,” he told the Post.

But as much of an honor for Harper as the All-Star Game will be, this development came over the objections of Nationals Manager Davey Johnson, who was rooting against Harper in last week’s vote in hopes that the rookie could use the All-Star break to get some much-needed rest. (Harper hasn’t missed a game since being called up to the majors in late April.)

And it throws a crimp in Harper’s midseason vacation plans. Originally, Harper had intended to use the four-day break to fly home to his family in Las Vegas. Instead, he’s headed to Kansas City, but his family will be flying in for the occasion.

The Major League Baseball All-Star Game begins 8:15 p.m. tomorrow and will be broadcast on Fox.