India, June 20 -- Just as the USMNT were gearing up to begin their second FIFA World Cup group-stage fixture against Australia, a sudden and unexpected setback emerged from inside the camp only moments before kickoff.

Christian Pulisic has been ruled out of Friday's clash against Australia due to a calf injury, with Ricardo Pepi set to replace him in the starting lineup, USMNT manager Mauricio Pochettino confirmed to FOX Sports.

Pulisic had been instrumental in the team's opening win over Paraguay, providing an assist and playing a key role in forcing an own goal, helping drive the USMNT's dominant performance.

Pulisic was forced off at half-time during the USA's 4-1 opening win over Paraguay last week after picking up a calf injury an...