"Honestly, we almost ran out of baseballs," manager Matt Williams said. "Between he and Wilson (Ramos), whoever gets in the park first today and goes to the outfield will have lots of souvenirs."
Williams said Harper will begin a minor league rehab assignment after the Nationals begin a road trip next week.
"I'm still trying to see where my swing's at. ... I don't see myself coming back after five games or four games," Harper said. "I really want to push it and see how I feel after eight, nine games down there. If I feel good before that, then I'll see where I'm at."
Williams will have to do some shuffling when Harper returns. Ryan Zimmerman, whose chronic shoulder problems have moved him off third base, has been playing in Harper's spot in left field.
Williams originally said Zimmerman will move back to third, but now the manager says he will move players around depending on matchups and to give players rest. Zimmerman could be playing first base, third base or left field, while Harper will be used in all three outfield positions. Anthony Rendon will shuffle between second base and third base.
"It doesn't really matter to me. I just want to play," Harper said. "I just want to be in the lineup and hopefully I can come back and help the team win."
The Nationals have been playing well recently in Harper's absence, moving into first place in the NL East ahead of Thursday's opener of a four-game series against the Atlanta Braves.
"One through nine, everyone's swinging it really, really well right now. We're playing well. I'm the odd man out, I guess," he said jokingly.