Boateng, who will represent Ghana - an opponent of Germany in the group stage - at the World Cup this summer, told Germany's Sport Bild magazine that he had already offered his apologies several times to Ballack.
"All I can do is apologise," said Boateng, who is the half-brother of Germany international Jerome Boateng.
"I was just too late and I hit him straight on. It looked stupid. I apologised to him twice on the field and now for a third time.
"I am sorry. It was not intentional."
Ballack is still letting the realisation sink in that he is going to miss the World Cup due to the ankle injury he picked up from the tackle.
"Of course I am angry and it is disappointing. I don't want to comment on it yet," he said.
"When you get such a diagnosis just two or three weeks before a World Cup then it is bitter.
"But that is football. Things must go on. I am obviously disappointed and have just got to let it sink in."
Meanwhile, Ballack's agent Michael Becker has not ruled out taking legal action against Kevin-Prince Boateng.
He has no doubts that it was a premeditated attack.
"Every spectator could see what Boateng has done and that was clearly a premeditated foul," said Becker.
"It is not possible that somebody breaks the rules with the intent to cause injury.
"The football field is not outside the law, even if Boateng believes that."
Germany coach Joachim Low is looking to put the bad news behind him as quickly as possible and concentrate on preparing his squad in the best possible way for the World Cup.
"Clearly it is going to be harder without Ballack, but we still want to reach our objectives," he told the German football federation's official website.
"I am still convinced that we will play a successful World Cup."
Low does not intend to call any new faces into his squad, although that might change should any Bayern Munich player pick up an injury in the Champions League final on Saturday.
"We will first of all wait until after the Champions League final and hope that all of Munich's players remain healthy," he added.
Source: Team Talk
Source: Team Talk