Uiagalelei (coach's decision) is inactive but will serve as the emergency third quarterback against the Bills on Sunday, Eric Smith of the Chargers' official site reports.
The Chargers signed Uiagalelei to the active roster Saturday to provide depth at quarterback due to the uncertainty around the status of Trey Lance (groin). Lance has been cleared to play Week 3 and will be Justin Herbert's backup. As the emergency QB3, Uiagalelei is prohibited from playing Sunday unless both Herbert and Lance were to leave the game due to injury, illness or ejection.