This morning ESPN.com golf writer Bob Harig reported that PGA Tour pro John Daly twice tweeted the personal cell phone number of a Florida sportswriter and encouraged his followers to complain to the sportswriter about an article he wrote on Daly’s “lengthy PGA Tour disciplinary file.”

Florida Times-Union sportswriter Garry Smits told ESPN he received several voicemails from Daly supporters over the last few days but added that none of the messages were threatening in nature.

While the tweets with Smits’ phone number have since been deleted, the question remains as to whether this invasion of privacy was the first of its kind on Twitter. Will athletes now do this sort of thing whenever the media publishes a story critical of them or do you believe this is an isolated incident? Have your say in the comments section below.

St. Louis Cardinals manager Tony LaRussa is suing Twitter and an unidentified Twitter user for impersonating him on the site, the St. Louis Post-Dispatch reports on its website.

Cardinals beat writer Derrick Goold writes that LaRussa filed the trademark infringement and “misappropriation of likeness and name” suit in San Francisco court last month. Twitter is based in San Francisco.

The suit alleges that the unidentified Twitter user impersonated LaRussa by creating an account in his name–@TonyLaRussa–an account which has since been removed and deleted. The user impersonating LaRussa made crude and vulgar comments on the page, including several about deceased Cardinals pitchers Darryl Kile and Josh Hancock. One now deleted tweet read “Lost 2 out of 3, but we made it out of Chicago without one drunk driving incident or dead pitcher,” a reference to Kile and Hancock.

The San Francisco Chronicle writer Philip Matier reports that LaRussa attempted to contact Twitter and have the account removed through his lawyer but received no response. Matier adds that the account disappeared “within a half hour of the trademark infringement complain being filed.”

Click here to access the official court documents. Enter “CGC09488101″ when prompted for a case number.

Update: June 6, 2009: Tony LaRussa and Twitter have reached a settlement on the case. The Associated Press has the details.

If you’re at all interested in the business of sports or in becoming a sports agent, you would do well to follow the sports agents on Twitter and learn as much as you can from them.

Drew Rosenhaus is one of the biggest sports agents in the business. Although his Twitter account is relatively new, he tweets on a regular basis and reading those tweets offer a glimpse into the busy world of a successful sports agent.

Mark Slough is President and CEO of Merge Sports & Entertainment, his own athlete representation firm. Slough’s clients include NFL standouts like the Patriots’ Sammy Morris.

Evan Morgenstein is President and CEO of PMG Sports, a company that represents many Olympians including Mark Spitz, Nastia Liukin and Amanda Beard.

Darren Heitner is a “must follow” for anyone interested in learning about the athlete representation business. Darren started his own representation firm, Dynasty Athlete Representation, and authors SportsAgentBlog.com, a blog about the sports representation business and sports industry in general. Sports agents Jason Belzer and Bryan Swalley also represent clients for Dynasty Representation.

While these sports agents maintain their own individual Twitter accounts, some agencies maintain Twitter accounts to publicize information about their clients. One such agency is Gaylord Sports, which has used its Twitter account to publicize new signings and client transactions.

Updates - Several retired NHL players have become NHL agents for Octagon Hockey in Minnesota including Ben Hankinson and Chris McAlpine. Allan Walsh is also an Octagon hockey agent and is based in Los Angeles.

Drew Carr is a sports agent based in Orlando, Florida, who specializes in golf and motor sports clients. James Heintz is a football agent based in St. Louis. Richard Vester is an NFL agent based in Florida.

ESPN announced yesterday morning that the NBA fined Dallas Mavericks owner Mark Cuban $25,000 for his Twitter comments on the officiating during a Mavericks game last week. This prompted Cuban to pose an interesting question on his “Blog Maverick” blog entitled Are Tweets Copyrighted?

Obviously Mark Cuban had to have known that he was risking a fine from the league office when he complained about the officiating publicly no matter which venue he used to communicate his displeasure. So, do you think the NBA is right for fining Cuban for his comments? What if his Twitter page was private and someone copied his tweet to the media? Does that change anything? Do you think this fine changes the way owners and athletes feel about using Twitter to communicate?