"It is such a travesty to me," Harper said. "I'm not saying this as disrespect to minor-leaguers -- the  Olympics are in Tokyo, and you're not sending big-league guys? Are you kidding me?
"You wanna grow the game as much as possible and you're not gonna let us play in the Olympics because you don't wanna cut out on money for a two-week period? Like, OK, that's dumb."
Baseball had been on a hiatus from the Olympic sports lineup since 2008. The sport was set to return this summer in Tokyo before the Summer Games were pushed to 2021 due to the coronavirus pandemic.
Team USA -- composed mostly Minor League Baseball players and a few veteran MLB free agents -- has yet to qualify for the Summer Games.
MLB shuns participation in the Games by its players because franchises fear diminished attendance and potential injuries to key players during the Olympics, which coincides with the U.S. professional baseball season.
Star players sometimes feel the same way, particularly about avoiding injuries that could affect their entire season or even their careers.
MLB stars take place in another global competition -- the World Baseball Classic -- but that tournament occurs during the off-season.
"The 2021 Olympics are next year," Harper said. "Why not shock the world and put all your big-leaguers back in it?"
Harper also made a pitch to fellow baseball stars on Thursday on Instagram to gauge their interest. He tagged MLB, President Donald Trump, USA Baseball, Mike Trout, Mookie Betts, Cody Bellinger, Christian Yelich and Aaron Judge.
"Who's in? Olympics 2021? Let's get it," Harper wrote.
"Let's get it done fellas!"