Liverpool striker Luis Suarez apologized for his "inexcusable behaviour" after biting Chelsea's Branislav Ivanovic, the BBC reported.
The incident occurred during Sunday's 2-2 tie.
"I've spoken to Ivanovic on the phone and I could apologise directly to him. Thanks for accepting," Suarez tweeting, according to the report.
Suarez said in a statement earlier, "I apologise to my manager and everyone at Liverpool for letting them down."
Blues defender Ivanovic, 29, complained to referee Kevin Friend that he had been bitten on his right arm by Suarez inside the Chelsea penalty area.
Ian Ayre, Liverpool's managing director, said, according to the BBC, "Luis is aware that he has let himself and everyone associated with the club down. We will deal with the matter internally and await any action from the Football Association."
Suarez had been given a seven-match ban for biting PSV Eindhoven midfielder Otman Bakkal in November 2010.