Meanwhile, Jennings' Leinster colleague Cian Healy took a knock to his eye during the England game. Following further investigation, it has been confirmed that the prop has an injury to his eye socket.
The Ireland squad and management will depart for the World Cup on Tuesday. Medical advice has dictated that Healy's departure date for the tournament has been put back by four days, so he will fly out at a later date to join up the rest of the squad.
The injury could rule Healy out of Ireland's first pool match against the USA on Sunday, September 11.