Christian Pulisic was subbed out at halftime during the USMNT's World Cup opener against Paraguay with no official reason initially given for the change.
https://www.foxnews.com/sports/christian-pulisic-subbed-halftime-usmnt-world-cup-opener-feeling-tightness-calf
https://www.foxnews.com/sports/christian-pulisic-subbed-halftime-usmnt-world-cup-opener-feeling-tightness-calf