 He made his Premier League debut on 21 August 2013 at Stamford Bridge against Chelsea, replacing the injured Ciaran Clark a few minutes before half-time.Okore made his first Premier League start on 24 August in Villa's home game against Liverpool.On 16 September 2013, Villa announced that Okore will be sidelined for the 2013–14 season after suffering a ruptured anterior cruciate ligament injury in his right knee in a game against Newcastle United on 14 September; the injury required season-ending surgery.