Barcelona winger Raphinha was substituted in the first half on Friday in Philadelphia.
The CBF did not say how long he would be sidelined for, but Brazilian website Globo Esporte reported he could be fit to return for a possible game in the last 16, which starts in two weeks' time.
"The player will follow an intensive treatment protocol under the supervision of the Brazilian national team's medical team, with the goal of recovering and returning to action as soon as possible," the CBF said in a statement.
Raphinha struggled with various injuries to his right thigh last season.
Brazil coach Carlo Ancelotti could turn to either of the 19-year-old duo of Endrick and Rayan, or Arsenal's Gabriel Martinelli, to replace Raphinha.
Five-time world champions Brazil, who have four points from two games, round off their Group C campaign against Scotland on Wednesday in Miami.
That game could provide Neymar, sidelined for a month with a calf injury, a first international appearance since October 2023.