"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'.
Boateng, born in Berlin to a Ghanaian father and a German mother, has had an uneasy relationship with German fans ever since his days playing at Hertha Berlin.
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.
The irony is that the 23-year-old Berlin-born midfielder who has also played for Tottenham Hotspur, will take part in the World Cup playing for Ghana while his half-brother Jerome is in the preliminary Germany squad for the June 11-July 11 tournament.
To make matter worse, Ghana are in Germany's Group D, and play each other on June 23 in Johannesburg.
Ballack, who will miss out on what would have been his third World Cup, flew to Sicily on Monday after the scan revealed a tear of one ankle ligament and a partial tear on another that will leave him out of action for eight weeks.
On Tuesday he said there was no need for bad blood.
"Of course I am very angry and disappointed but in football one should let it go," he said.
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