The Lions medical team have confirmed the injury requires at least 10-14 days treatment following a scan on Tuesday.
It is the belief of the Lions management team that it would be better for the player to receive intensive treatment in Cardiff. The management have always had the expectation that travelling players should be fit to play the first game on tour.
A replacement player will be announced in due course.
However, once Leigh Halfpenny is fully fit he will rejoin the Lions in South Africa. This will take the tour party back to 37 players as originally announced but was reduced to 36 following the injury to Welsh centre Tom Shanklin.