Oxlade-Chamberlain fell awkwardly after a clumsy challenge by Carlos Gruezo in England's 2-2 draw at Sun Life Stadium in Miami on Wednesday night.
The Arsenal winger went for a scan on Thursday and initial reports suggest he will be out for two to three weeks because of a ligament strain.
If Oxlade-Chamberlain returned to training within a fortnight, he could potentially return for England's second Group D match against Uruguay in Sao Paulo on June 19.
But the 20-year-old's chances of playing the England's first Group D match against the Italians in Manaus five days earlier look remote.
Oxlade-Chamberlain hobbled out of the Sun Life Stadium without the aid of crutches.
The former Southampton player emerged from England's team hotel in Florida wearing a knee brace on Thursday morning though.