Munster confirmed on Monday that Springbok prop BJ Botha will be sidelined for up to a month, following a calf injury he sustained in last Friday's pre-season clash with London Wasps at Musgrave Park.

It is a huge blow for the veteran Bok's World Cup prospects.

Even though he was rated as an outside chance of selection only, he was part of South Africa's extended squad that gathered in Cape Town and Johannesburg prior to the Boks' international season.

Botha, who played in his first game after a knee injury ruled him out of South Africa's Tri-Nations campaign, was forced to retire in the 28th minute last Friday.

A medical examination confirmed he had suffered a calf tear that will see him miss Munster's opening games in the PRO12 League - which begins on September 3, with the game against The Dragons in Cork.

Good news for Munster is that James Coughlan, who was also forced to retire (eye injury), has been given the all clear and he is available to be named in the squad for Friday's pre-season clash with London Irish.

There is further good news, with Tomas O'Leary having trained with the Munster squad on Monday, after his surprise omission from the Ireland World Cup squad.

Darragh Hurley (Achilles) and development contracted Troy Smith (cruciate) will not be considered for that game, nor will Johne Murphy, who damaged a hamstring while playing with the Ireland Select XV.

However, Murphy does expect to be in contention for a place in the squad for the Dragons game.