Justin Ontong is the latest South African to be struck by injury after his return to the side © Cricinfo Ltd

Justin Ontong, the South Africa allrounder, has been ruled out of the next two ODIs against West Indies with a knee injury. However, captain Graeme Smith will be fit to lead the side after overcoming his own knee problem.

Ontong made 23 in South Africa's six-wicket win in the opening match of the series at Centurion Park but will now miss the matches in Cape Town and Port Elizabeth. He has recently returned to the international fold after an absence of three years.

"Justin tweaked his knee during the Pro20 game on Friday, and though he played through the pain on Sunday, he will not be available for selection for the next two matches," said coach Mickey Arthur. "However, Graeme [Smith], who also has as bit of a knee injury, will be fine. He's a tough character. We'll monitor Dale Steyn's hamstring injury but he's looking good."

Arthur also suggested that South Africa may tinker with the balance of their side and they currently have an expanded 15-man squad to pick from because of the injury concerns.

"We'd like to give Morne (Morkel) some more game time, but if we select him for Friday, there will be another bowler who will be very unlucky not to play," he added. "We're still not sure of the make-up of the team for Friday, but we will probably play a spinner here."