Black Cats boss Paolo di Canio had bombed out Bardsley after mocking comments of their opening day defeat to Fulham on social media.
The defender commented: "I would like to apologise to the club and supporters for my comments made on social media.
"I understand how they may have been interpreted and it was a serious error of judgement.
"I accept the punishment that has been handed to me by the football club and will now focus my attention and efforts on rehabilitation and regaining my fitness."
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