The boy, believed to be 11, was stabbed during a skills camp involving several dozen young players at a pitch in the Topsail neighbourhood of Conception Bay South, a suburban town just west of St. John's.
According to sources close to the family, the boy remained sedated in serious but stable condition in a St. John's hospital on Saturday morning.
Witnesses said a teenager ran out onto the field shortly before 8 p.m. AT and stabbed the boy in the neck, leaving parents, coaches and other players reeling in shock.
Nicholas Layman, 19, was charged with aggravated assault and assault with a weapon at a Friday court appearance.
Charges of attempted murder were added later that day.
Layman is set to appear in provincial court on Oct. 3 following a seven-day psychiatric assessment at the Waterford Hospital, a psychiatric hospital in the west end of St. John's.