West Ham striker Carlton Cole was fined by England's Football Association on Wednesday for jokes he made on Twitter during England's friendly against Ghana last month.
The FA said Cole was warned about his future conduct and fined 20,000 pounds ($32,800).
Cole joked that the match at Wembley Stadium was a trap by the British government to find illegal immigrants. He deleted the comment but was still charged.
The players' union in England also issued a Twitter warning on Wednesday.
''It is ironic that at a time when players are accused of being distant and out of touch with supporters that attempts to communicate can bear such potential sanctions,'' Bobby Barnes, deputy chief executive of the Professional Footballers' Association wrote on the organization's website.
Barnes stressed the need for players to be vigilant when using Twitter and other social networking websites.
''We would advise players not to stop tweeting but to bear in mind that this is not an intimate private conversation but a medium open to a potentially wide audience,'' Barnes said. ''A useful point to consider in posting tweets might be whether you would be comfortable in being so open with a journalist either from written or news media.
''It is also worth bearing in mind that something that may appear humorous or harmless when spoken can take on a totally different dimension when put down in print.''
