With Sale climbing up to second place in the Gallagher Premiership, Dan du Preez has been impressing alongside his twin brother Jean-Luc along with elder sibling Rob at the Sharks.
De Klerk has been particularly impressed with Dan du Preez and claims the back-row should be on the verge of adding to his four previous caps for the Springboks in the near future.
"Dan is playing amazing and it hasn't just come all of a sudden. He had a massive year last year and was very unlucky to drop out injured before the World Cup," De Klerk said.
"Duane Vermuelan is still in the picture but as his stats show, Dan is playing phenomenal rugby. He has so much going for him and there really isn't a weak point and the du Preez boys bring it every weekend.
"Dan is definitely being looked at and if you perform the coaches will look at you. It's not a like a few years ago when they would just focus on South African based players. Now, if you do well at your club you are going to get a chance and that is the main motivation."