BUENOS AIRES, July 29 (Reuters) - Pumas prop Ramiro Herrera's World Cup chances hang in the balance after a knee ligament and cartilage injury requiring surgery and up to six weeks recovery, the Argentine Rugby Union (UAR) said on Wednesday.
Tighthead Herrera was injured during last weekend's 34-9 loss to Australia in their Rugby Championship test in Mendoza that leaves Argentina bottom of the standings with no points.
"Ramiro Herrera suffered a rupture of the internal ligament and inside meniscus of his (left) knee and must have an operation," Argentina doctor Guillermo Botto said.
"His recovery will need between four and six weeks approximately," Botto said in a UAR statement.
Coach Daniel Hourcade has called up Juan Pablo Orlandi, whose last Pumas test was against England in November 2013, in Herrera's place for their Aug. 8 clash with South Africa in Durban.
Wing Gonzalo Camacho is a notable absentee from the 26-man touring party having made an impressive comeback against the Wallabies after two years out due to a shoulder injury.
Camacho, replaced after 55 minutes, came through the match unscathed but his absence is due to rotation of the squad as Hourcade looks at all his World Cup options.
"The objectives for the match with South Africa are the same as for the previous ones, to go gradually improving our game, get more rhythm and evaluate players ahead of the World Cup," Hourcade said.
"The last match was very intense and in the final minutes it cost us (dear) to keep up that rhythm," he said.
Argentina were in the match until near the end before giving away two of the Wallabies' four tries in the last three minutes.
South Africa narrowly lost their tests against the Wallabies and All Blacks, taking two bonus points.
"We must prepare for a very hard battle, improving our individual tackling and rhythm," Hourcade said.
"South Africa are a great team, they could have won both their matches and lost them at the end... It will do us a lot of good to play a team like that."
An Argentina XV, meanwhile, including some fringe Pumas will travel to Montevideo for a match against World Cup bound Uruguay on Saturday. (Writing by Rex Gowar in London; Editing by Greg Stutchbury)