The Wearside club have reportedly forced winger James McClean to delete his Twitter account due to a controversial tweet involving the IRA.
The 23-year-old wrote on the social network site that his favourite song was 'The Broad Black Brimmer', which is a well-known IRA theme.
The message sparked DUP MP Gregory Campbell to accuse the Irishman of making 'contentious' comments due to the song's content.
The controversy is believed to have prompted Sunderland into telling McClean to close down his Twitter account, according to the Irish Independent.
McClean was recently at the centre of criticism when he refused to wear a poppy on his Sunderland shirt to mark Remembrance Day last year.
When he received death threats he contacted Northumberland police - which is an interesting action considering his anti-English beliefs.
When asked about his 'dislike' of poppies he replied: "I won't wear one on my shirt next year, either. I'm not cared what people say."