"I am sorry. It was not intentional. I just came in too late and made full contact. It looks pretty stupid," the German told Sport Bild online.
The apology coming three days after the foul during the FA Cup final between Portsmouth and Ballack's Chelsea did little to dampen German anger directed at Boateng.
The 33-year-old Chelsea midfielder was injured in the first half of Saturday's match against Portsmouth, limping off during his team's 1-0 win after a late tackle by Boateng.
Fans on Tuesday vented their anger on dozens of websites, calling him 'public enemy number one; and setting up chatrooms called '82 million against Boateng' or 'Anti-Boateng Group'.
He is also a distant relative to German football hero, Helmut Rahn, who scored Germany's winning goal in the 1954 World Cup final against Hungary.
To make matter worse, Ghana are in Germany's Group D, and play each other on June 23 in Johannesburg.
"Of course I am very angry and disappointed but in football one should let it go," he said.
