Rees was replaced by Richard Hibbard in the 56th minute of yesterday’s 43-17 defeat by the Springboks after suffering the injury during a tackle.

The Llanelli Scarlets front row went for a scan in a Bloemfontein hospital last night when it was confirmed he will be out for two weeks.

Cardiff Blue Thomas has been called up as replacement and is expected to arrive in Johannesburg tomorrow morning, before joining the squad for training.

Thomas won the last of his 26 caps as a substitute in last November’s defeat by South Africa at the Millennium Stadium.

Wales forwards coach Robin McBryde said: “This is a big disappointment for Matthew, especially as he’s an important part of the team right now.

“He’s enjoyed a good tour so far and we know he has definitely benefited from the experience of playing in South Africa.

“We’re lucky that Rhys Thomas is familiar with life inside the squad and so we’re confident that he’ll be able to adapt quickly.

“It won’t be easy for him slotting straight into the tour but he’s an excellent player and he’ll be ready to play a part on Saturday.”