The 22-year-old Soto was initially in Tuesday's starting lineup against the St. Louis Cardinals, but the Nationals announced the IL move about an hour before the contest and scratched him. According to the team, he was moved to the injured list with a strained left shoulder.
Soto will now have to sit out at least the next seven games, as the Nationals have only three off-days during his IL stint.
Veteran outfielder Yadiel Hernandez was recalled from the Nationals' alternate site to replace Soto on the roster. Andrew Stevenson filled in for Soto in right field during Tuesday's matchup against the Cardinals and went 1-for-3 with a run scored.
The Nationals earned a 3-2 win over the Cardinals.
In 14 games this season, Soto -- the 2020 National League batting champion -- has a .300 batting average with two home runs, eight RBIs and a stolen base.