Stormers flanker Burger, capped 68 times by his country, injured his knee at the end of February but there has been no progress in his rehabilitation according to Allister Coetzee, his club coach.
"The position with Schalk is very frustrating and we are going to get a full assessment shortly from a physician on where it should be taken from here but you can take it as read that we won't see Schalk play before the end of this season," said Coetzee.
Meanwhile, in-form Sharks back Pietersen, a veteran of 45 Tests, suffered a fractured thumb during his side's Super Rugby final defeat to the Chiefs.
He will undergo surgery on Wednesday and has been replaced in the squad by Stormers centre Juan de Jongh, who was a controversial omission by 'Boks coach Heyneke Meyer from the original squad in the first place.
"We decided to pick Juan as he provides midfield cover, an area where we are perhaps a bit thin now that JP is out," said Meyer.
"Losing JP is obviously a massive blow as he's been playing some superb rugby lately, but Juan has also been in good form for the Stormers and was one of the unlucky players to miss out on initial selection."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
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The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.