Nationals manager Jim Riggleman said he expects the 18-year-old Harper will get at least one at-bat in the game.
"I'm hoping that he kind of blends in," Riggleman said. "I'm not looking for him to excel against major league pitching."
Harper is learning a new position, moving from catcher to the outfield. Nationals outfielder Jerry Hairston said it will take time to make the adjustment.
"He's got a good head on his shoulders," Hairston said. "We've talked a little bit. He's a humble guy. He realizes what's going on. I'm sure everybody's excited about watching him play. He's a great talent. It's a spring training game. I know he's going to be a little excited."
Jayson Werth, who signed a $126 million, seven-year contract with Washington in the offseason, will not make the trip. Neither will All-Star third baseman Ryan Zimmerman and first baseman Adam LaRoche. Their debuts will likely come Tuesday or Wednesday when Washington hosts the Mets and the Florida Marlins.